What is the BEST oil to use?

[UnleashedBeast]

This is a good question that was sent to me, and I would like to answer it publicly.

 

What about the flow rate or characturistics between 5w-30 and 10w30? Do you need the 5W to lubricate the bearings better? There is another oil thread going on in the Shelby GT tech forum and everyone pretty much says 5W-30 for supercharged engines not becuase of wieght of the oil but the way it can flow into the bearing surfaces.

First things first, the first number shouldn't mean anything to you if you live in a warm climate, and especially if you have a supercharged car. Both the 5W-30 and 10W-30 are both going to be the exact same viscosity at normal engine temperatures.

Take a look at this graph, and then at the explanation and thoughts beneath it.



All 4 lubricants are the same viscosity @ 100*C (212*F) Normal engine temps. The differences are, how much more do other formulations thicken as they cool in comparison to each other.

Cold start wear occurs when the engine lubricant has cooled and thickened. It's too viscous at initial start up to fully lubricate the engine bearings, and has more trouble getting to the upper passages in the heads. This is why we want to select an engine lubricant in the 5W-30 for a daily driver that could see all temps, or 0W-30 in extremely cold environments.

This is what the graph above tells me.

Amsoil 10W-30 is about the same viscosity as Mobil 1 5W-30 at 0*C (32*F) *Amsoil 5W-30 being less viscous*.....so all of you that are using a group III base stock in a 5W-30 formulation, it's safe to use a 10W-30 in a true synthetic. Thanks to the superior cold characteristics of a group IV base stock.

The lower the number is at 0*C (32*F) on the chart, the less time a lubricant will require to achieve full operational temperatures, and the least amount of start up wear. However, all four of these lubricants are so close, the difference on cold starts from 32*F (0*C) and above will make no difference.

What is the advantage of a 10W-30 true synthetic versus the 5W-30 refined petroleum/true synthetic blend?

1. Shear stability - will resist thinning under heavy pressures and usage (i.e. supercharger) better than a 5W-30. The wider the viscosity spread, the greater the chance an engine oil will shear. (i.e. 0W-30 will shear more than 10W-30)

2. NOACK volatility - This lubricant is rated at 5.7%, less mass lost due to evaporation means less oil will vaporize. This means less oil being caught in your catch cans, or fogging back into your air intake manifold. A 5W or 0W oil would have 6.7-8.6% loss (group IV base stocks) and 10-12% loss (group III base stocks). Since you are not cranking your engine under 32*F daily, it's a waste to use them. NOACK has proven recently to be more important than ever before. Detergent additives (TBN) disipate slower when the lubricant has a lower NOACK Volatility percentage.

 

Amsoil Signature Series ATM 10W-30 has the lowest NOACK ever, 5.3%

I can safely assume that most northerners store their Shelby during the winter, and they never come out until the weather has no chance of freezing. Yet another reason 5W-30 isn't a requirement, especially for a supercharged car.

[kahmann]

^Guess I'm switching to 10W30. Thanks for the extremely detailed posts - very enlightening.

[UnleashedBeast]

^Guess I'm switching to 10W30. Thanks for the extremely detailed posts - very enlightening.

 

 

You are very welcome. I recall a few months ago when a few GT500 owners were baffled about my choice of 10W-40 versus the recommended 5W-50. Someone even said I was going to destroy my engine. Well, after all of the graphs, explanations, UOAs, and logic.....I'm not the only one using Amsoil 10W-40 any longer.

 

Ford got carried away calling for a 50 grade oil for the 5.4L supercharged mill.

 

If there are any questions, I'm here for answers. If my reply isn't prompt, I may have forgotten to check on this thread. PM me to check it.

[07SGT]

I am curious. Jim of JDM may not know jack about lubrication technology but I am sure he knows what works.

 

I also used to drink the Amsoil Kool Aid but changed when I received the test results from oil analysis. The Amsoil, for our fleet, did not hold up as promised by Amsoil. This was confirmed by oil analysis and yes, it was the oil analysis company recommended by Amsoil.

 

And you do not, correct me if I am wrong, have to use synthetic for the GT 500. The oil must meet the specs as established by Ford which includes dino based oils. The same goes for the Corvette and others that come standard with Mobil One. Mobil One has to meet GM specs but some dino oils meet the same specs. This is not to necessarily discredit synthetic oils as I know they have some advantages.

[SGT2417]

^To UnleashedBeast.

 

Thank you for the very informative article on Oil weight and viscosity. I understand much better now and admit that i was wrong in what i said about how not to use 30w oil. It is true that the almighty dollar controls everything and would easily explain why Ford says use 20w. I will be switching to 10w-30 Royal purple. I have used it in the past and was pleased with it. Also i get the commercial discount through Napa.

 

Is anyone sure that there is a difference in the ford racing fl-820s oil filter versus the standard fl-820s oil filter?

[UnleashedBeast]

I am curious. Jim of JDM may not know jack about lubrication technology but I am sure he knows what works.

 

Motorcraft will work in the engine, and is sufficient protection when used at lower mileage change intervals. No arguing that. I don't do sufficient, I want to know what's best. His statement that Royal Purple is crap is what triggered my post, and the reasons why. I just didn't leave it at saying he was wrong, I proved how he is wrong.

 

I also used to drink the Amsoil Kool Aid but changed when I received the test results from oil analysis. The Amsoil, for our fleet, did not hold up as promised by Amsoil. This was confirmed by oil analysis and yes, it was the oil analysis company recommended by Amsoil.

 

 

I would like to get more info on this. What vehicle/engine, miles of use, filters used, climate, location, etc.. What was expected, what was achieved, can I see a UOA that made you change your mind? What lubricants are you using now, etc...

 

What was negative about the UOA that made you change your mind? Once, there was an engine that was switched to a much better lubricant from a cheaper formulation. The first UOA showed wear metals higher than the previous oil used. First assumption would be, the new oil isn't working as well as the previous fill, but this is not the truth. The new oil was cleaning out all the crap accumulated in the engine that the cheaper oil couldn't remove. After a few changes, the wear metals were lower than ever.

 

I don't drink the Amsoil Kool Aid, I drink the PAO (group IV) and POE (group V) base stocks are superior to group II and group III base stocks. Guess that means I'm drinking the Amsoil, Red Line, and Royal Purple Kool Aid.

 

And you do not, correct me if I am wrong, have to use synthetic for the GT 500. The oil must meet the specs as established by Ford which includes dino based oils. The same goes for the Corvette and others that come standard with Mobil One. Mobil One has to meet GM specs but some dino oils meet the same specs. This is not to necessarily discredit synthetic oils as I know they have some advantages.

 

 

You are correct, synthetic oils are not a 100% requirement, and some dino/petroleum based lubricants meet some manufacturers specs. This goes back to the, what's sufficient and what's the best, debate. In fact, the Motorcraft 5W-50 lubricant that is formulated by Conoco Phillips isn't a true synthetic, it's a group III hydrocracked highly refined petroleum.

 

Thank you for the very informative article on Oil weight and viscosity. I understand much better now and admit that i was wrong in what i said about how not to use 30w oil. It is true that the almighty dollar controls everything and would easily explain why Ford says use 20w. I will be switching to 10w-30 Royal purple. I have used it in the past and was pleased with it. Also i get the commercial discount through Napa.

 

There are instances where a 20 grade oil would be in good use, especially when you are using cooling mods. If you are running a cooler thermostat, and the oil is running 20-30*F cooler than before, then a lighter viscosity would be better suited for the engines use. This is also assuming the car isn't being used for road racing.

 

There was a recent case with a custom built GT500 engine that had oil pressure issues. Conventional 10W-30 oil was being used for break in, and 80 psi pressures were being observed at only 2,500 rpm. The engine builder wasn't pleased with this, so we made the decision to lower the viscosity to 5W-20 (RD20 Amsoil Racing oil). This is an engine that was spec'd for a 5W-50, although I have already proven that this is way to heavy for this application (even stock). There is so much more involved with choosing the proper lubricant than simply reading the oil cap.

[07SGT]

Motorcraft will work in the engine, and is sufficient protection when used at lower mileage change intervals. No arguing that. I don't do sufficient, I want to know what's best. His statement that Royal Purple is crap is what triggered my post, and the reasons why. I just didn't leave it at saying he was wrong, I proved how he is wrong.

 

 

 

I would like to get more info on this. What vehicle/engine, miles of use, filters used, climate, location, etc.. What was expected, what was achieved, can I see a UOA that made you change your mind? What lubricants are you using now, etc...

 

What was negative about the UOA that made you change your mind? Once, there was an engine that was switched to a much better lubricant from a cheaper formulation. The first UOA showed wear metals higher than the previous oil used. First assumption would be, the new oil isn't working as well as the previous fill, but this is not the truth. The new oil was cleaning out all the crap accumulated in the engine that the cheaper oil couldn't remove. After a few changes, the wear metals were lower than ever.

 

I don't drink the Amsoil Kool Aid, I drink the PAO (group IV) and POE (group V) base stocks are superior to group II and group III base stocks. Guess that means I'm drinking the Amsoil, Red Line, and Royal Purple Kool Aid.

 

 

 

You are correct, synthetic oils are not a 100% requirement, and some dino/petroleum based lubricants meet some manufacturers specs. This goes back to the, what's sufficient and what's the best, debate. In fact, the Motorcraft 5W-50 lubricant that is formulated by Conoco Phillips isn't a true synthetic, it's a group III hydrocracked highly refined petroleum.

 

 

 

There are instances where a 20 grade oil would be in good use, especially when you are using cooling mods. If you are running a cooler thermostat, and the oil is running 20-30*F cooler than before, then a lighter viscosity would be better suited for the engines use. This is also assuming the car isn't being used for road racing.

 

There was a recent case with a custom built GT500 engine that had oil pressure issues. Conventional 10W-30 oil was being used for break in, and 80 psi pressures were being observed at only 2,500 rpm. The engine builder wasn't pleased with this, so we made the decision to lower the viscosity to 5W-20 (RD20 Amsoil Racing oil). This is an engine that was spec'd for a 5W-50, although I have already proven that this is way to heavy for this application (even stock). There is so much more involved with choosing the proper lubricant than simply reading the oil cap.

 

 

 

First, let me apologize for the kool aid remark. That was inappropriate. We used the amsoil 0w-30 in Ford 4.6 2v engines. The 0w-30 is their signature oil and is supposed to be their absolute best. It is supposed to last, I believe, about 25-30,000 miles. It did not. We used it in several vehicles, about 4 or 5 and it never made it past 15 K and even then the TBN dropped drmatically. The engines did not have crud in them at them time. The engines were all newer and very well maintained with an exceptional high quality dino based oil. Yes, if you switch to another oil it can clean - scour an engine and that is dangerous when crud, varnish, sludge, etc can clog an oil passage. I agree with you. We are in the midwest where the temperature is very moderate. It usually will not drop below 15-20 degrees BELOW zero in the winter and usually will not exceed 100 in the summer. At least it is not extreme. Though I wonder what could be more extreme. We also used the amsoil filters.

 

We switched back to Ultra Lux. Ultra lux is a dino oil that is not hydra cracked. The molecules are not cracked due to heat or processing. Ulta Lux has liquid moly. The engines last well over 200 K miles under extreme service without any oil related failures. We have not had a valve cover or oil pan removed in over 10 years with a fleet of 15 vehicles. Each car averages about 25,000 miles per year. We do suffer the occasional water pump, probably on about 20% of the vehicles and have had a few cracked intake manifolds. Occasional transmission and rear end failures, again only on about 25% of the vehicles. OUr mechanic is an old race engine builder and designer with great success. I read everything I could about oil in the past, including the PAO issues and eventually switched to amsoil in my private vehicles. I have now switched to the Ultra Lux. Ultra Lux is used mostly in fleet vehicles and big 18 wheelers. It has been shown to increase mileage and reduce wear due to a reduction in friction.

 

Again, I used to use amsoil and thouight it was the best, based on test results and stats. But in the real world it did not perform for us. I also do not trust a company that will only sell oil, or any product, on a pyramid scheme type sales organization. I agree that synthetics certainly have their advantages.

 

What is always fun is to talk to corvette owners that brag about how their corvettes REQUIRE Mobil One synthetic oil. Then I read the owners manual to them where Mobil One is suggested, but not required, and then read the specs the oil must meet. Then you show them bottles of dino oil from Castrol, Pennzoil, Quaker State, Valvoline and others that meet the specs. They look like a deer in the headlights and don't know if they have been shot, screwed, or snake-bit.

 

But you have presented very informative information for all to consider. I did read once before that Ford saved .16 of a mile per gallon by switching to 20 weight oil. When you are trying to comply with CAFE standards every little bit helps. sixteen hundreths here, less weight in the vehicles, technology, computers, it all adds up for increased mileage. Less weight can translate to less force to overcome and subsequently more HP. And the lighter oil flows marginally quicker for heat exchange. All things to consider. I am curious if Ford changed the side clearances on the 4.6 when they went from 5w-30 to 5 w-20. Or was it only to gain fuel economy?

[Kvin C]

I'm curious about that sticker, as well. I've never seen it, nor have I ever heard of it before this thread.

 

 

Dunno if there is still interest in this aspect of the thread, but here is a photo of the sticker on the hood of my 2007 SGT. Note that it has been placed over a very similar decal, presumably the original Ford Mustang one that probably calls for 5W-20.

 

 

Now of course, in that "unique mystique", Shelby's SGT Supplement handbook found in the glovebox tells you to always use 5W-20 oil (!!).

 

(The same Supplement Handbook also warns you to "..never powershift...." and also advises against the use of snow chains).

[UnleashedBeast]

First, let me apologize for the kool aid remark. That was inappropriate. We used the amsoil 0w-30 in Ford 4.6 2v engines. The 0w-30 is their signature oil and is supposed to be their absolute best. It is supposed to last, I believe, about 25-30,000 miles. It did not. We used it in several vehicles, about 4 or 5 and it never made it past 15 K and even then the TBN dropped drmatically.

 

and why I always tell people to stick with the severe service schedule of up to 15,000 miles or one year on Amsoil top tier lubricants. The new 0W-30 (it has recently been reformulated), no longer carries the outrageous 35,000 mile claim. It's been reduced to 25,000 like the other top tier lubricants they formulate. In a car that is easy on oil, 25,000 miles is possible (on easy highway miles), but not in a muscle car, forced induction applications, service vehicles, short trip use, towing, excessive idling, etc. 15,000 miles is my limit on any top tier lubricant.

 

So in a nut shell, it did live up to the severe service claims of 15,000 miles.

 

Amsoil SSO 0W-30 is now AZO <----- click here

 

Oh, and no worries about the Kool Aid remark. Just wanted everyone to know that I'm not biased on brand, only ingredients. :beerchug:

 

Again, I used to use amsoil and thouight it was the best, based on test results and stats. But in the real world it did not perform for us. I also do not trust a company that will only sell oil, or any product, on a pyramid scheme type sales organization. I agree that synthetics certainly have their advantages.

 

 

It wouldn't be like this if the retail giants would have given Amsoil a chance in the 70's. They shuned the owner of Amsoil away. Now that's a successful company, the owner is loyal to his dealers that made the company what it is today.

 

Actually it kinda is a pyramid, but kinda isn't. If an independent dealer reaches a certain volume he breaks free of his sponsor. It's different, but none of that matters to me. I'm a dealer just so I can buy it for myself, friends, and family all for dealer cost. The testing for the Shelby gave me something to do more focused towards my hobby.

 

What is always fun is to talk to corvette owners that brag about how their corvettes REQUIRE Mobil One synthetic oil. Then I read the owners manual to them where Mobil One is suggested, but not required, and then read the specs the oil must meet. Then you show them bottles of dino oil from Castrol, Pennzoil, Quaker State, Valvoline and others that meet the specs. They look like a deer in the headlights and don't know if they have been shot, screwed, or snake-bit.

 

on on the other end of that argument.....everyone thinks Mobil 1 is the bees knees because it is the factory fill in more OEM cars than any other lubricant. That's not because it's better, it's because Exxon Mobil and GM both benefit from the partnership. It's brand recognition marketing.

 

But you have presented very informative information for all to consider. I did read once before that Ford saved .16 of a mile per gallon by switching to 20 weight oil. When you are trying to comply with CAFE standards every little bit helps. sixteen hundreths here, less weight in the vehicles, technology, computers, it all adds up for increased mileage. Less weight can translate to less force to overcome and subsequently more HP. And the lighter oil flows marginally quicker for heat exchange. All things to consider. I am curious if Ford changed the side clearances on the 4.6 when they went from 5w-30 to 5 w-20. Or was it only to gain fuel economy?

 

 

No clearance changes at all. The federal government makes the manufacturer pay a fine for every .1 mpg they fall short of the average of 27.5 mpg. So .16 means $$$$ saved!

[blueone]

How many miles you got on your Shelby now? Happy with the 10W-30 so far? I'm going to try some Amsoil 10W-30 next change.

 

 

Just shy of 2,000 on the new short block and about 6,500 on the heads, I used MC 5w-30 in my first build and decided to make a change with this one and use the RP. I ran dino during break in for the first 1,000 miles, so I can't really give an informed opinion on how well it holding up since it.s only been in for about 1,000 miles.

[sgt1020]

Going to order new Oil. Should I do 5w-30 or 10w-30??? Why one over the other? Which will protect the motor better under hard driving conditions and high heat?

 

My mods are listed in my signature incase you want to know.

 

Also, I use Royal Purple. Should I do Amsoil or is the RP just as good?

[07SGT]

Another issue we discovered with using Amsoil, and I presume any extended service oil, is the contamination. Again, this was through ongoing oil analysis. We discovered silicon levels that were too high and apparently cumulative over 15+ K miles. Even the best filter, including amsoil filters, did not filter out the silicon particles. That is why I feel it is best to change the oil every 2-3 K miles and keep it exceptionally clean inside the engine. Yes you could obtain the same results by changing any synthetic at 2-3 K miles also.

[UnleashedBeast]

Going to order new Oil. Should I do 5w-30 or 10w-30??? Why one over the other? Which will protect the motor better under hard driving conditions and high heat?

 

My mods are listed in my signature incase you want to know.

 

Also, I use Royal Purple. Should I do Amsoil or is the RP just as good?

 

Use either oil, both will do well. If you store your car in the winter, go ahead and use 10W-30 instead. It will offer better shear stability and less burn off/evaporation.

 

If you are a winter driver, and start your car at 32*F or less everyday, or more than once a day, I would opt for 5W-30 during the winter months.

 

Another issue we discovered with using Amsoil, and I presume any extended service oil, is the contamination. Again, this was through ongoing oil analysis. We discovered silicon levels that were too high and apparently cumulative over 15+ K miles. Even the best filter, including amsoil filters, did not filter out the silicon particles. That is why I feel it is best to change the oil every 2-3 K miles and keep it exceptionally clean inside the engine. Yes you could obtain the same results by changing any synthetic at 2-3 K miles also.

 

Let's assume that a vehicle will have a 20 ppm silicon contamination after 3,000 miles of use, and is using an extended drain oil. After 6,000 miles, the silicon would be around 40 ppm, assuming the source of contamination was linear. And so on, and so on. This is a natural occurrence.

 

On the other hand, we are focusing on the "best" engine lubricants for supercharged and high horsepower applications, not on extended oil change intervals. The issues you experienced would have been the same with any long OCI drain oil, as you have already noted, not just Amsoil. There are still advantages of using top tier oils for shorter drain intervals.

[07SGT]

Correct me if I am wrong but I believe the Motorcraft 5W-50 is the only oil that is recommended or meets the requirements for the GT 500.

[UnleashedBeast]

Correct me if I am wrong but I believe the Motorcraft 5W-50 is the only oil that is recommended or meets the requirements for the GT 500.

 

 

The actual spec, yes....

 

but other lubricants are formulated better and are far beyond the minimum specs set forth by Ford.

[07SGT]

The actual spec, yes....

 

but other lubricants are formulated better and are far beyond the minimum specs set forth by Ford.

 

 

Correct me if I am wrong, but I believe the difference involves possible contamination to the catalytic converter. If that is the case, and if the converter is damaged, it would not be covered under warranty.

[07SGT]

Correct me if I am wrong, but I believe the difference involves possible contamination to the catalytic converter. If that is the case, and if the converter is damaged, it would not be covered under warranty.

 

[UnleashedBeast]

Correct me if I am wrong, but I believe the difference involves possible contamination to the catalytic converter. If that is the case, and if the converter is damaged, it would not be covered under warranty.

 

 

NOACK Volatility, it's yet another advantage of a true synthetic base stock (group IV and V).

 

It's the measurement of the % of mass loss of a lubricant at a very high specific temperature in a given amount of time. It's called burn off/evaporation. Phosphorous is the agent that destroys catalysts over time.

 

these are average numbers

 

true synthetics (group IV and V) lose 6-8%

hydrocracked synthetics (group III) lose 10-12%

conventional lubricants (group II) lose 13-15%

 

So, with that being said.

 

The API doesn't take NOACK volatility into consideration when deciding the maximum levels of ZDDP allowed in an API SM or API SN certified lubricant. The sad thing is, they should.

 

Since a true synthetic base stock has less burn off and loses less of the additive pack due to a lower NOACK, it's also known that it will release lower amounts of ZDDP. This means a true synthetic base stock can have higher levels of ZDDP, yet contaminate a catalyst no more than a group III or group II base stocks with lower amounts of ZDDP.

 

This is where it really gets funny! Amsoil, Red Line, and Royal Purple lubricants are still formulated with levels of ZDDP that were acceptable for API SL and SJ certifications. This was of course when the federal government only required factory installed catalysts to be warrantied for 80,000 miles. Now it's beyond 100,000 miles and the manufacturers and the API created new certifications to only allow lower levels of ZDDP. Hey, the manufacturers don't want the expense to replace cats after a car is 8+ years old.

 

This is where is gets REALLY funny. People who are worried about the older formulations destroying their cats. Especially since the superior base stocks won't do it any faster than the newer formulations with lower amounts of ZDDP. If the older formulations guaranteed the manufacturer that the cat would survive at least 80,000 miles, even with inferior/cheap engine lubricants, shouldn't people today feel confident with true synthetics? Even beyond 100,000 miles?

 

and even funnier!

 

How many people on a car modding forum either....

 

A. Delete their cats for more performance

B. Go to a high flow metallic spun cat that isn't effected by phosphorous like ceramic cats are

C. Sell their car long before it would become an issue for the original owner.

 

and there you have it. This is nothing to worry about. Like the Nike slogan for years......"Just Do It!"

[07SGT]

NOACK Volatility, it's yet another advantage of a true synthetic base stock (group IV and V).

 

It's the measurement of the % of mass loss of a lubricant at a very high specific temperature in a given amount of time. It's called burn off/evaporation. Phosphorous is the agent that destroys catalysts over time.

 

these are average numbers

 

true synthetics (group IV and V) lose 6-8%

hydrocracked synthetics (group III) lose 10-12%

conventional lubricants (group II) lose 13-15%

 

So, with that being said.

 

The API doesn't take NOACK volatility into consideration when deciding the maximum levels of ZDDP allowed in an API SM or API SN certified lubricant. The sad thing is, they should.

 

Since a true synthetic base stock has less burn off and loses less of the additive pack due to a lower NOACK, it's also known that it will release lower amounts of ZDDP. This means a true synthetic base stock can have higher levels of ZDDP, yet contaminate a catalyst no more than a group III or group II base stocks with lower amounts of ZDDP.

 

This is where it really gets funny! Amsoil, Red Line, and Royal Purple lubricants are still formulated with levels of ZDDP that were acceptable for API SL and SJ certifications. This was of course when the federal government only required factory installed catalysts to be warrantied for 80,000 miles. Now it's beyond 100,000 miles and the manufacturers and the API created new certifications to only allow lower levels of ZDDP. Hey, the manufacturers don't want the expense to replace cats after a car is 8+ years old.

 

This is where is gets REALLY funny. People who are worried about the older formulations destroying their cats. Especially since the superior base stocks won't do it any faster than the newer formulations with lower amounts of ZDDP. If the older formulations guaranteed the manufacturer that the cat would survive at least 80,000 miles, even with inferior/cheap engine lubricants, shouldn't people today feel confident with true synthetics? Even beyond 100,000 miles?

 

and even funnier!

 

How many people on a car modding forum either....

 

A. Delete their cats for more performance

B. Go to a high flow metallic spun cat that isn't effected by phosphorous like ceramic cats are

C. Sell their car long before it would become an issue for the original owner.

 

and there you have it. This is nothing to worry about. Like the Nike slogan for years......"Just Do It!"

 

 

Yes the NOACK volatility is an issue that Amsoil uses to their advantage. Mind you I am not particularly against Amsoil, or even against synthetics in general. But another spec to pay for close attention to is the TBN. I found that Amsoil, when analyzed, did not maintain the TBN as advertised. And the silicon is a real problem on any extended oil change, as mentioned. There are other issues with synthetics which is why they have not been recommended for air cooled engines in aircraft. One school of thought is that the synthetic oils do not transfer heat the way a conventional oil does. The synthetic, being so molecularly stablized is not effected by the heat and may not absorb the heat allowing transfer to the cooling fins (or radiator in a liquid cooled engine). As such the synthetic oil provides lubrication but may not provide the transfer and removal of heat from the engine. It seems that dino oil, especially an oil that has not had its hydrocarbons cracked in processing, may be superior for transference of heat. That may be why the synthetics do not react, or break down, when exposed to heat.

 

I wish there was one standardized testing procedure that would allow everyone to objectively judge oil and filters but, alas, there is not.

[07SGT]

Going to order new Oil. Should I do 5w-30 or 10w-30??? Why one over the other? Which will protect the motor better under hard driving conditions and high heat?

 

My mods are listed in my signature incase you want to know.

 

Also, I use Royal Purple. Should I do Amsoil or is the RP just as good?

 

SGT 1020; Not trying to hijack a thread but where did you purchase the windshield banner for the SGT. That is the best I have seen!!!!!!

[UnleashedBeast]

But another spec to pay for close attention to is the TBN. I found that Amsoil, when analyzed, did not maintain the TBN as advertised.

 

 

You were using Amsoil in a severe service application, and you don't still don't feel that it lived up to its claims?

 

Normal OCI = 25,000 miles *this is only going to happen with cars that are highway driven only with long miles per trip and are easy on oil*

Severe Service OCI = 15,000 miles *everything else you could use oil for*

 

This is why I recommend maximum oil change intervals to 15,000 miles or 1 year, whichever occur first, when using top tier Amsoil formulations.

 

Here is a test for you. Go buy Mobil 1 EP *guaranteed for 15,000 miles*, test it in one of your fleet vehicles, and report back. I bet you will find that the TBN in their formulation would not perform as well as Amsoil.

 

as far as heat, I would have to disagree. True synthetics create less friction, and therefore less heat. I've also never read any articles from anywhere that suggest a group II base stock would transfer heat more efficiently than a group III, IV, or V.

 

Oils that have ash (ash is commonly found in auto lubricants) content are not suitable for aircraft engines of any kind. They call for ashless formulations. It has nothing to do with the base stocks.

[07SGT]

I believe Mobil One had a synthetic for air cooled aircraft engines and withdrew from the market. They also paid a lot of claims for inspections and damages.

[UnleashedBeast]

I believe Mobil One had a synthetic for air cooled aircraft engines and withdrew from the market. They also paid a lot of claims for inspections and damages.

 

 

Mobil 1 formulates lubricants with group II, II+IV, III, and IV base stocks. There is more to damage to an engine than which base stock is chosen. The damage will most likely come from the additive package first.

 

Could you find more information on this? I'm interested in the topic.

[07SGT]

Mobil 1 formulates lubricants with group II, II+IV, III, and IV base stocks. There is more to damage to an engine than which base stock is chosen. The damage will most likely come from the additive package first.

 

Could you find more information on this? I'm interested in the topic.

 

I will do my best to find it for you. There have also been papers written on the subject of synthetics providing lubrication (superior) but not the absorption and transfer of heat. If the lubricant does not absorb the heat it cannot transfer the heat. And if it does not absorb the heat it is less likely to break down, which it does not.

[07SGT]

October 25, 1995

 

Mobil AV-1 Under Attack

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A class-action lawsuit demands that thousands of TCM 470-, 520-, and 550-series engines that used Mobil AV-1 synthetic oil be grounded for tear-down inspection and overhaul at Mobil's expense. We urge owners not to panic.

October 25, 1995

by Mike Busch

 

This article originally appeared in THE AVIATION CONSUMER and is reprinted here by permission.

 

 

 

About the Author ...

 

 

Mike Busch is editor-in-chief of AVweb, a member of the technical staff at Cessna Pilots Association, and in a prior lifetime was a contributing editor for The Aviation Consumer and IFR Magazine. A 6,000-hour commercial pilot and CFI with airplane, instrument and multiengine ratings, Mike has been flying for 36 years and an aircraft owner for 33. For the past 14 of those years, he's owned and flown a Cessna T310R turbocharged twin, which he maintains himself. In his never-ending quest to become a true renaissance man of aviation, Mike's on the verge of earning his A&P mechanic certificate. Mike and his wife Jan reside on the central coast of California in a semi-rural area where he can't get DSL or cable TV.

 

 

 

 

 

 

 

Complete Coverage from AVweb

(Links to Related Articles)

 

 

Primary Coverage

 

Mobil AV-1 Under Attack

 

Settlement Reached in Mobil AV-1 Class-Action Lawsuit

 

Mobil's Handling of AV-1 Claims Questioned

 

Supplemental Articles

 

Mobil AV-1 Engine Inspection and Repair Protocol

 

Mobil AV-1 Notice of Settlement

 

Press Release: Mobil AV-1 Settlement

 

Mobil AV-1 Claim Form

 

 

 

 

 

Even though Mobil AV-1 has been off the market for nearly a year, concerns about engine damage attributable the synthetic oil continue to skyrocket. Hundreds of former AV-1 users have submitted damage claims to Mobil for premature cylinder wear, stuck rings, clogged prop hubs and governors, and various other powerplant maladies. Mobil has been quietly reimbursing claimants for repairs, and some owners have taken Mobil to court.

 

The latest wrinkle is a voluminous class-action lawsuit filed in April, 1995, which seeks to force Mobil to notify owners of the thousands of Teledyne Continental 520- and 550-series engines formerly operated on AV-1 oil that they should immediately ground their airplanes and submit their engines to a complete teardown inspection, and to require Mobil to pick up the tab for both inspection and repair.

 

This class-action suit is being brought by Malvern J. Gross, Jr., a 60-year-old retired partner of the Price-Waterhouse accounting firm who now lives in the San Juan Islands near Seattle. Gross is a 5,000-hour pilot, ex-president of the National Aeronautics Association, on the board of EAA, and has owned seven different airplanes since he started flying in 1955. Armed with the results of teardown inspections of two low-time AV-1 engines and the testimony of several world-class powerplant experts, Mal Gross appears determined to get the word out that AV-1 can ruin engines, cause catastrophic engine failures, and jeopardize life and limb.

 

Gross's suit is being handled by Lieff, Cabraser, Heimann & Bernstein of San Francisco, a law firm that specializes in large class-action cases and participated in the $4.25 billion silicone gel breast implant settlement, the $2.2 billion GM pickup truck settlement, and the $5.26 billion Exxon Valdez verdict. We'd guess Mobil is taking the suit seriously.

 

Unlike most of the owners suing Mobil, Gross doesn't appear to be doing this for the money, but because he passionately believes that his fellow aircraft owners must be warned of the grave danger of continuing to fly behind an engine that may have been contaminated by AV-1 use. On the day Gross filed his class-action suit, his lawyers sent a three-page press release plus the full 37-page complaint to the editors of numerous aviation publications.

 

While we commend Gross for his good intentions and believe he has an important story to tell, we're concerned that language of his lawsuit will panic a lot of owners unnecessarily. AV-1 oil had serious problems and undoubtedly damaged some engines. But we don't expect AV-1 engines to start falling from the sky without warning, as the lawsuit might suggest.

 

Mal Gross's Experience

 

N210MG is a Cessna T210L that Gross purchased new in 1975. He's put 2,900 hours on the plane since then. In November 1991, Gross brought his airplane to Victor Aviation in Palo Alto, California, to have its Continental TSIO-520-R engine majored. Victor overhauled the engine to new limits, and Gross picked up the airplane in January 1992. After 30 hours, he drained the break-in oil and started using Mobil AV-1. He continued to use AV-1 until mid-1994, changing oil and filter every 50 hours.

 

During this period, a series of compression checks revealed a deteriorating trend of leakage past the rings. In September 1993, a mechanic removed the prop from Gross's T210 and found significant sludge accumulation in the forward hollow portion of the crankshaft, which he cleaned out.

 

When Mobil announced that they were withdrawing AV-1 from the market in June 1994, Gross immediately switched to AeroShell W100 and hoped his compression would start to improve. But checks in October 1994 and January 1995 showed further deterioration, with compression readings in the low-to-mid 60s.

 

Gross decided to take the plane back to Victor Aviation for borescope inspection in January 1995. The engine now had 590 hours SMOH. The borescope revealed signs of ring damage and excessive blow-by. Victor pulled the #5 jug and found the cylinder wall scored and the oil control ring badly stuck as a result of sludge accumulation. They also pulled the prop and discovered a golfball-sized accumulation of sludge in the crankshaft. At this point, Victor recommended removal and inspection of all six cylinders, and Gross approved.

 

Gross also hired his own independent engineering consultant, Dr. Michael Wood of Aircraft Engine Failure Investigation, Inc., and a member of the well-respected aviation department of San Jose State University.

 

When Victor removed and inspected all six cylinders and looked inside the crankcase, they were so alarmed by the extensive sludge deposits that they advised a complete engine teardown to determine the condition of the crankshaft and bearings. Dr. Wood concurred with this recommendation, and Gross agreed to have it done.

 

The teardown revealed main bearings that were worn, crazed, and heat-distressed. Some showed evidence of shifting, and one bearing tang had scored the crankcase supports enough to require the case to be sent out for repair. The oil transfer collar was scored. The lifter faces were pitted. All of this was evidence of lubrication failure, and of an engine that might have failed catastrophically if it had been operated much longer.

 

Thick syrupy black sludge was. found coating the insides of the crankcase, oil cooler adapter plate, crankshaft, and crankcase oil galleys. John Pava of Victor believes this sludge contamination explains the lubrication failure that damaged the bearings and transfer collar. Dr. Wood told Gross that he was "a very lucky man" for having had the engine torn down when he did.

 

Ronnie Eriksson's Story

 

Meantime, half a world away, a Swedish industrialist named Ronnie Eriksson was also having problems with the engine in his. 1988 Beech B36-TC Bonanza. Eriksson is a 1,700-hour pilot and flies his Bonanza all over Europe on business. Its Continental TSIO-520-UB engine was run exclusively on Mobil AV-1 oil after the factory break-in oil was drained.

 

Like Gross, Eriksson was concerned about a deteriorating trend of compression readings, and about the accumulation of lead sludge found when the propeller was removed during routine maintenance. Eriksson was also plagued by high CHT and oil temperatures, for which he compensated by running the engine extra-rich.

 

In February 1995, with 633 hours total time on the airplane, Eriksson had his engine crated and shipped to Victor Aviation for inspection and repair. After receiving and inspecting engine, Victor informed Eriksson that he was probably looking at a complete teardown and major overhaul which would ground his Bonanza for months. Eriksson jumped on an airliner and flew to California to assess the situation personally. He brought with him his own engineering consultant, Ulf Dahlquist, who had been Chief Inspector for the Swedish equivalent of the FAA. So Eriksson, Dahlquist, Wood, and Pava all wound up inspecting Eriksson's torn-down engine.

 

Dr. Wood characterized the innards of Eriksson's engine as the blackest and filthiest he had ever seen in his career. The case halves, oil pan, suction screen, crankshaft bore, oil pump, and piston domes all had extreme buildups of heavy black syrupy sludge similar to that seen in Gross's engine but worse. The oil control rings were stuck, the main and rod bearings showed indications of lubrication distress. Dahlquist and Pava both reported severe cam lobe wear and spalling, and at least one main thrust bearing worn completely through to the shell. All three experts agreed that the engine would have been at risk of catastrophic in-flight failure had it been continued in service.

 

Because Eriksson is not a U.S. citizen, he is not formally a plaintiff in the Gross v. Mobil lawsuit. But his engine and testimony figure prominently in the documents filed with the court.

 

A Long Time Coming

 

Mobil introduced its 100% synthetic AV-1 piston aircraft engine oil with great ballyhoo in connection with the 1986 round-the-world Voyager flight. It went on the market in 1987, after five years of R&D and 25,000 hours of flight testing in 23 different aircraft.. Teledyne Continental enthusiastically approved AV-1 for use in all TCM engines with oil filters. It didn't take long before isolated cases of lead sludge accumulation became apparent in some (but certainly not all) engines using AV-1. Both John Frank of the Cessna Pilots Association and yours truly started advising against the use of AV-1 in low-utilization owner-flown airplanes as early as 1991. Our rationale was that 100% synthetic oil is a superb lubricant but a lousy cleanser, and that cleansing is extremely important in piston aircraft engines because of their loose tolerances and the significant blow-by that can leak past the rings and contaminate the oil. But while we suggested owners not use AV-1, we honestly didn't anticipate that the lead sludging problem could reach the severity revealed by the Gross and Eriksson teardowns.

 

All the while, Mobil continued to promote AV-1 with an extremely aggressive advertising campaign that made grandiose claims for the product: "a cleaner engine with little or no sludge, a 200-hour oil change interval, up to 30% less oil consumption, 10º-15ºF cooler CHTs, and up to 5% fuel savings." Many knowledgeable engine people considered some of these claims to be exaggerated commercial puffery, and most considered Mobil's suggested 200-hour oil change interval to be insane. But owners lined up to buy AV-1 at eight bucks a quart.

 

Then, in a move that caught most observers by surprise (and delighted us), Mobil announced in June 1994 that it had decided to withdraw AV-1 from the market and to repurchase all existing inventory stocks. Mobil's press releases characterized this move as a marketing decision.

 

At the same time, however, Mobil sent a letter to owners of TCM 520- and 550-series engines stating that Mobil had just learned "during the past month" that in those engines "under certain conditions, the lubricant is not dispersing lead from the fuel as well as had been predicted on the basis of original flight and factory tests." Since then, Mobil has been quietly processing and settling individual owner claims for AV-1 damage. (See "Mobil's Position.")Why did it take so long for these problems to show up? The reason appears to be that the most seriously affected engines were in owner-flown airplanes that flew only 100 or 150 hours a year. (See "Which Engines Are At Risk?") Ronnie Eriksson's Bonanza is a good case in point. Erikson started using AV-1 in 1988, not long after it went on the market. He experienced symptoms of severe wear at only 633 hours, but it took him nearly seven years to accumulate those hours.

 

What We Think About This

 

It's important to keep all this in perspective. During the eight years that AV-1 was on the market, thousands of owners used it and the vast majority had good luck and no mechanical problems. Some noted an abnormal accumulation of lead sludge when the engine was torn down at overhaul, but most didn't. Only a relative handful appear to have suffered accelerated wear. We are unaware of any case of in-flight engine failure as a result of AV-1 use.

 

Nevertheless, we do not doubt that the Gross and Eriksson engines were badly trashed and at serious risk of seizure had they continued to be flown. And we do not dispute the suggestion that perhaps dozens or hundreds of other engines might be in the same boat.

 

The point is, however, that engines will almost surely exhibit clear warning signs of impending trouble long before internal damage becomes severe enough to cause in-flight engine stoppage. This was demonstrably true of both the Gross and Eriksson engines, and of several other engines we've followed that had to be overhauled prematurely after using AV-1.

 

The contaminated engines all exhibited deteriorating compression within 200-400 hours after starting AV-1 usage. Cylinder removal consistently revealed abnormal top-end wear, stuck and sludge-fouled oil control rings, and a thick coating of black sludge on the underside of pistons and on visible portions of the crankcase interior. Prop removal revealed a heavy accumulation of sludge in the hollow portion of the crankshaft and in the prop hub, and after the sludge was flushed out, it often redeveloped within 100 hours.

 

Consequently, it should be relatively easy for maintenance-aware owners of AV-1 engines to determine whether or not they are at risk. The great majority of them will not be. The notion that all AV-1 engines should be torn down as a precautionary measure seems to us like a colossal over-reaction.

 

We certainly don't want to sound like apologists for Mobil. It is inconceivable that they weren't well aware of the lead scavenging problems of AV-1 years before they withdrew it from the market. Mobil's own pipeline-patrol airplanes reportedly stopped using AV-1 because it gummed up their engines. Mobil engineers surely knew that Mobil marketing people were overstating the benefits of the product. We think Mobil should have yanked AV-1 a lot sooner than they did. Mobil should have come clean about AV-1's shortcomings and publicly announced their damage compensation policy, rather than quietly dealing with disgruntled owners on a case-by-case basis.

 

Mobil deserves to have their hands slapped over the AV-1 affair. But neither Mobil nor owners should be required to tear down or replace an engine unless clear evidence exists that the particular engine is at risk.

 

Specific Recommendations

 

If you used AV-1 in your engine for 100 hours or more (whether or not you're still using it or not), you should check compression regularly (we suggest every 50 hours when you change oil) and be alert for signs of deterioration. If you observe this, particularly in a turbocharged engine, you might be well advised to investigate further for signs of abnormal lead sludge deposits. The easiest way to accomplish this is to pull the prop and look for sludge accumulations in the hub and crankshaft. If those areas appear clean, you're probably home free.

 

If the crank and prop appear to be fouled with black sludge, you might borescope your cylinders or perhaps even pull off a jug or two and inspect for abnormal cylinder wear and sludge-fouled pistons and oil-control rings. While the cylinder is off, you can inspect the inside of the crankcase for black deposits, and inspect the cam lobes for evidence of lubrication failure.

 

Another danger sign in an AV-1 engine is any abnormality in propeller operation. Both Gross and Eriksson engines had badly scored transfer collars, and one owner we spoke to discovered that his engine was lead-fouled only after discovering that he could not control prop RPM.

 

Only if clear evidence of serious contamination is found would we consider doing a precautionary engine teardown inspection.

 

Status of the Lawsuit

 

Gross et al. v. Mobil Corporation et al. was filed in early April, 1995, in Federal District Court in San Francisco. With lightening speed (by judicial standards), the Court certified the class-action suit as a mandatory ("non-opt-out") class. According to our legal eagles, what this means is that all U.S. owners of TCM 520 and 550 series engines that used Mobil AV-1 are automatically parties to the lawsuit, and furthermore the class action probably will be their only legal remedy against Mobil. While denying the claims of the plaintiffs, Mobil did not argue against the Court's certification of the class...probably because it protects Mobil against having to defend hundreds or thousands of individual legal actions.

 

The Court also granted the plaintiffs' request for an order requiring Mobil to send letters to every TCM 520 and 550 owner of record, notifying them of the lawsuit and the plaintiffs' claims, and instructing them how to contact the plaintiffs' law firm for more information. (You can contact Lieff, Cabraser, Heimann & Bernstein by telephone toll-free at 1-800-956-1009, by FAX at 1-415-956-1008, or by email at lch@crl.com.)

 

In September, 1995, the Court granted a plaintiffs' motion to expand the class to include owners of TCM 470 series engines as well. Once again, Mobil stipulated to the motion without a fight. The Court also set a tentative trial date in November, 1995.

 

AVweb will continue to follow this situation closely and report any further significant information as we receive it. Readers with AV-1 experiences to report are encouraged to contact us by email at editor@avweb.com.

 

Mobil's Position

 

When TCM 520- and 550- owners were notified in June 1994 that it was pulling AV-1 from the market, Mobil's letter included an 800-number for owners to call if they believed they had "an oil-related mechanical problem directly attributable to your use of AV-1."Mobil is now dealing with at least 250 acknowledged owner claims of AV-1 engine damage, and we suspect the number is likely a good deal higher. At first, calls to the 800-number were being handled by John Esser and Frank Feinberg of Mobil's marketing company, Mobil International Aviation and Marine Sales, Inc. Later, claimants were referred to R. C. Gronwaldt in Mobil Corporation Claims.

 

Owners who called Mobil were sent a claim form and asked to submit photocopies of logbook pages, maintenance invoices, photographs, and other proof of the legitimacy of their claim. Some were asked to send Mobil pistons or other parts for inspection.

 

Most bona-fide claimants were quietly and politely offered reimbursement for a top overhaul, pro-rated to TBO. Many owners accepted this offer. Some who made a fuss were offered reimbursement for major overhaul or a factory reman (again, pro-rated to TBO) plus prop and governor overhaul and engine R&R labor. Mobil has consistently refused to compensate claimants for aircraft downtime, nor for engine mount or hose replacement or turbocharger and controller overhaul.

 

One owner we talked to has had his aircraft down for more than six months. Mobil offered to settle with him for nearly $18,000 covering a $26,000 factory reman pro-rated to TBO plus prop, governor, and R&R. This owner, whose airplane is extremely critical to his business, refused Mobil's offer and is suing.

 

To date, Mobil's handling of AV-1 claims has been strictly on a "squeaky-wheel" basis. Mobil has not notified owners that AV-1 might have damaged their engine, nor publicized the fact that Mobil is offering some reimbursement for engine repairs and replacement.

 

To claimants, Mobil admits that they are aware of cylinder damage, stuck rings, and contaminated propellers and governors resulting from inadequate lead scavenging by AV-1 oil. But Mobil apparently insists to this day that they know of no case in which bottom-end damage was directly attributable to AV-1, and dismiss as "impossible" the idea that AV-1 users might face increased risk of in-flight engine failure.

 

Mobil also contends that top-end damage attributable to AV-1 is strictly to confined to TCM 520- and 550-series engines, and has so far has refused (we're told) to accept claims from owners who used AV-1 in 360s and 470s or in any Lycoming engine. We are at a loss to explain how Mobil rationalizes this position.

 

While most of the owners we talked to had elected to accept the settlement offered by Mobil, a few did not feel they were being treated fairly and are going to court in hopes of obtaining what they considered to be full and fair compensation. We have no way of knowing at this point just how many owners are suing Mobil over AV-1, but the number of lawsuits is probably significant.

 

Which Engines Are At Risk?

 

Why were some engines so severely contaminated by AV-1 while most remained clean and healthy? Nobody really knows the answer yet. But we can make some educated guesses.

 

It's important to understand the mechanism at work here. Synthetic oil like AV-1 is composed of long, smooth polymer molecules that don't have all the little side branches that petroleum polymers do. This makes them extremely slippery and gives them excellent lubricating properties. Synthetic oils also lack the "light ends" of petroleum oils that can break down under extreme heat and create varnish and carbon deposits.

 

But it's those same smooth, ultra-slippery molecules that give synthetic oil its Achilles' heel: the inability to hold lead salts and other contaminants in suspension. The synthetic oil molecules are simply too damned slippery to hang onto such contaminants, so they settle out of solution and form sludge deposits, particularly in areas of oil stagnation such as prop hubs, oil pans, and the inside of pistons.

 

Tetraethyl lead is an octane enhancer used in avgas. It doesn't belong in the oil. Two compression rings on each piston seal the combustion chamber and keep combustion confined to where they belong. As long as the rings do their job well, the lead will go out the exhaust pipe and the oil will stay relatively lead-free.

 

But if combustion byproducts leak past the compression rings, a vicious cycle can begin. The third piston ring is the oil control ring, a spring-loaded slotted ring that receives oil from tiny feed holes in the piston and is responsible for spreading an oil film on the cylinder walls. If exhaust blows by the compression rings and fouls the oil control ring, its ability to lubricate the cylinder walls is compromised. Lack of lubrication results in accelerated wear of the cylinder and rings, further reducing compression and creating more blow-by. Within a few hundred hours, the compression may be down to the low 60s and the engine may be filthy with gooey black sludge. Some blow-by is inevitable, and engine oil is supposed to hold a reasonable amount of contamination in suspension so it may be drained out at the next oil change. Unfortunately, AV-1 didn't do this as well as petroleum-base oils.

 

We believe that AV-1 engines that exhibit good compression test results are probably not at much risk of sludge formation and sludge-induced lubrication problems. Engines that exhibit early deterioration of compression are at greatest risk.

 

Turbocharged engines appear to be much more likely to be contaminated because their higher combustion chamber pressures make blow-by more of a problem. The Gross and Eriksson engines were both turbo'd, and every owner we talked to in researching this article turned out to have a turbocharged engine. Ironically, AV-1 was especially popular among owners of turbos because of its resistance to coking under high heat.

 

It looks to us as if low-utilization engines (typical of most owner-flown aircraft) are more likely to be contaminated than ones that fly every day (such as Part 135 operators). The oil film on cylinder walls tends to strip away during periods of disuse, resulting in cylinder wall corrosion and metal-to-metal scuffing at the next engine start. Hence, low-utilization engines tend to wear cylinders faster.

 

At oil-change time, the sump should be drained immediately after flight while the oil is still hot and agitated. Otherwise, contaminants have time to settle out of suspension and form sludge deposits. This is good practice for all kinds of oil, but was especially crucial with AV-1.

 

The use of extended oil change intervals (as touted by Mobil's a

[UnleashedBeast]

Thanks for the reading material.

 

I'm also on BITOG reading up on this topic.

[07SGT]

Thanks for the reading material.

 

I'm also on BITOG reading up on this topic.

 

 

Sorry it was so long. There is more info on the lawsuit and Mobil One did agree to pay for inspections and repair to engines. We had another problem with synthetic oil products. We were using Amsoil in the rear end, 75-140. The rear end went out and when opened we noticed the inside of the housing was covered with a sludge. The sludge was apparently a combo of fluid and dust from the clutches. It had to be cleaned out and did not just flow out with the fluid. Again, synthetic may lubricate well but there are also questions if it absorbs sludge, varnish, dirt, etc.

[6-Speed]

And you do not, correct me if I am wrong, have to use synthetic for the GT 500. The oil must meet the specs as established by Ford which includes dino based oils.

 

Here is the title for the WSS-M2C931-B spec that Ford recommends for the GT500:

 

OIL, ENGINE, API SM, SAE 5W-50 INITIAL FILL AND SERVICE FILL FULL SYNTHETIC

[6-Speed]

The same goes for the Corvette and others that come standard with Mobil One. Mobil One has to meet GM specs but some dino oils meet the same specs.

 

 

What is always fun is to talk to corvette owners that brag about how their corvettes REQUIRE Mobil One synthetic oil. Then I read the owners manual to them where Mobil One is suggested, but not required, and then read the specs the oil must meet. Then you show them bottles of dino oil from Castrol, Pennzoil, Quaker State, Valvoline and others that meet the specs. They look like a deer in the headlights and don't know if they have been shot, screwed, or snake-bit.

 

According to the 2010 Corvette Owner's Manual, the service fill must meet the GM4718M "High Performance" oil spec. It appears that all the compliant "registered" oils, at least on this list, are synthetic.

 

http://www.gm.com/corporate/responsibility/environment/maintenance/gm_approved_engine_oils.pdf

 

Starting in 2011 the dexos1 approvals supersede GM4718M and GM6094M. I believe all the dexos1 approved oils are either full synthetic or a blend.

 

http://www.gmdexos.com/licensedbrands.html

[07SGT]

According to the 2010 Corvette Owner's Manual, the service fill must meet the GM4718M "High Performance" oil spec. It appears that all the compliant "registered" oils, at least on this list, are synthetic.

 

http://www.gm.com/corporate/responsibility/environment/maintenance/gm_approved_engine_oils.pdf

 

Starting in 2011 the dexos1 approvals supersede GM4718M and GM6094M. I believe all the dexos1 approved oils are either full synthetic or a blend.

 

http://www.gmdexos.com/licensedbrands.html

 

 

You are apparently correct. They have changed the specs since June 2009. Before that you could meet the GM specs with a conventional oil, even if it recommended Mobil One.