0-20w oil

[B-train]

Is it possible to be more specific about which motor oils GM recommends for the 6.6L L8T, besides just '5W30 synthetic'?
Are there any unique standards called out, above & beyond '5W30 synthetic'?

I don't believe there are any unique standards. Just 5w-30 Dexos oil is called out. Same oil as specified for the 6.0L gas motor in the previous HD line.

 

[Marky Dissod]

The 6.6L L8T will accept ANY 5W30 Dexos motor oil? REALLY?
Find it hard - but not impossible - to believe. But if true, deeply disappointing.
Was hoping for more specificity on GM's part.

My budget and time constraints force me to settle for
0W20 / 0W30 / 5W20 / 5W30 Group IV synthetic -
but I'd still like to know how far down I'm stooping.

Stopping at 'good enough for GM's recommendation' always left a bad taste in my mouth.
It irked me that the LT1 in sedans / wagons called for 'whatever 5W30 you find'
but the nearly identical LT1 in the 'vette of the same years not only specified synthetic 5W30,
it only allowed 5W30 that passed the 'GM 4718M' standard.

Was hoping the L8T had a higher standard than lesser EcoTec engines.

 

[BlaineBug]

In my 2019, I plan on switching to 5w30 after my remaining stock (a single oil change worth) of 0w20 is exhausted.

 

[BlaineBug]

Here’s a copy of a GM warranty from 1970. 12 months /12k miles BTB,5/50 powertrain. Still think warranties were better 50 years ago?


View attachment 360129

Compare and contrast the price of that 1970s vehicle versus the similar equal of today, accounting for today's actual inflation (not the gimmicky fake news inflation numbers produced by mainstream propaganda media outlets) and let us just see how awful that 1970 warranty turns out to be. I wonder.....

 

[Fireman591]

Anybody using any other oil than the 0-20w it calls for? Just curious if it would hurt to use a say 5-30w? Thx

Walmart is carrying Dexos-D Mobil 1 https://www.walmart.com/ip/Mobil-1-...tor-Oil-0W-20-5-Quart/5020133446?from=/search

 

[Antonm]

Having been an engineer for one of the major OEMs, I can assure you that the voices of accountants and regulatory compliance officers are heard FAR more than that of engineers.

Its hilarious reading this thread, everyone talking "it was designed and engineered to run X oil", um no, no it wasn't. There hasn't been a totally new design in at least several decades, probably more (because why would you spend all that time on R&D money on something you already have), every new motor design is a copy /paste of a preexisting engine (one that the parent company has licence for) and then its modified to meet whatever new requirements' exist, at the cheapest possible cost, using only parts/ components' / lubricants from preferred suppliers.

I've personally had a situation where the clear, obvious, much better engineering choice was readily available at a very negligible price increase. Guess what, this major OEM used the slightly cheaper option from a preferred supplier because the MBA's make the final calls, not the engineers.

I know this is a diesel engine thread, but just as an example take the gasser 6.2 used in Tahoe/Yukon/Escalade and compare it to the 6.2 gasser found in the Corvette. They are more alike than they are different. The oiled components are identical, but GM say to use 0W40 in the corvette and 0W20 in the Tahoe/Yukon/Escalade. Nothing is different about the reciprocating assemblies between the engines, yet GM recommends two different oils. Why, because of CAFE, no other reason, the thinner oil is not better for anything other than helping GM meet a regulatory requirement.
...

 

[BlaineBug]

Having been an engineer for one of the major OEMs, I can assure you that the voices of accountants and regulatory compliance officers are heard FAR more than that of engineers.

Its hilarious reading this thread, everyone talking "it was designed and engineered to run X oil", um no, no it wasn't. There hasn't been a totally new design in at least several decades, probably more (because why would you spend all that time on R&D money on something you already have), every new motor design is a copy /paste of a preexisting engine (one that the parent company has licence for) and then its modified to meet whatever new requirements' exist, at the cheapest possible cost, using only parts/ components' / lubricants from preferred suppliers.

If personally had a situation where the clear, obvious, much better engineering choice was readily available at a very negligible price increase. Guess what, this major OEM used the slightly cheaper option from a preferred supplier because the MBA's make the final calls, not the engineers.

I know this is a diesel engine thread, but just as an example take the gasser 6.2 used in Tahoe/Yukon/Escalade and compare it to the 6.2 gasser found in the Corvette. They are more alike than they are different. The oiled components are identical, but GM say to use 0W40 in the corvette and 0W20 in the Tahoe/Yukon/Escalade. Nothing is different about the reciprocating assemblies between the engines, yet GM recommends two different oils. Why, because of CAFE, no other reason, the thinner oil is not better for anything other than helping GM meet a regulatory requirement.
...

I never knew that, that 0w40 is the recommended weight for the Corvette 6.2. Simultaneously, I was never of the thought process that the motors were any different!

 

[Antonm]

I never knew that, that 0w40 is the recommended weight for the Corvette 6.2. Simultaneously, I was never of the thought process that the motors were any different!

There are some differences in the fuel injection systems, the computer tuning is decently different from what I understand ( I’m not knowledgeable enough about the computer tuning in either, just what I’ve heard), belt drive and such. They’re very similar but not identical, and you could take either one and convert it into the other from a mechanical standpoint.

The important part for an oil discussion is the crank and cam bearing clearance specs, which are the same between the truck 6.2 and corvette 6.2, yet GM says they take different oils.
…

 

[Marky Dissod]

Having been an engineer for one of the major OEMs, I can assure you that the voices of accountants and regulatory compliance officers are heard FAR more than that of engineers.
...
I know this is a diesel engine thread, but just as an example take the gasser 6.2L used in Tahoe / Yukon / Escalade,
and compare it to the 6.2L gasser found in the Corvette. They are more alike than they are different.
The oiled components are identical, but GM says 0W40 in the corvette and 0W20 in the Tahoe / Yukon / Escalade.
Nothing is different about the reciprocating assemblies between the engines, yet GM recommends two different oils.
Why? Because of CAFE, no other reason.
The thinner oil is not better for anything other than helping GM meet a regulatory requirement.

This explains A LOT.
So far as I'm concerned, this is why I'd use 0W30 or 5W30 instead of 0W20 or 5W20.
(Don't think I drive hard enough to NEED 0W40.)
By the way, what kind of 0W40? I'm not a tribologist, but I know that not every 0W40 is identical to any other 0W40.

There are some differences in the fuel injection systems, the computer tuning is decently different from what I understand
(I’m not knowledgeable enough about the computer tuning in either, just what I’ve heard), belt drive and such.
They’re very similar but not identical, and you could take either one and convert it into the other, from a mechanical standpoint.

The important part for an oil discussion is the crank and cam bearing clearance specs, which are the same between the truck 6.2L and corvette 6.2L -
yet GM says they take different oils.

This is why I asked about the oil specified for the 6.6L L8T, as opposed to the lesser EcoTec V8s that are subject CAFE MpG test standards.

 

[15burban]

From my research the 0w40s especially pennzoil ultra platinum for the 6.4 srt's (challengers, chargers, ram 2500 and 3500) after a few thousand miles the oil shears down to a 30 weight. I don't know the scientific reason other then since it is such wide range going from a 0 (cold) to 40 (hot). That's based on uoa's from Blackstone I've seen. I run redline 0w30 in the winter and am going to be running redline 5w30 in my 16 6.4 ram. Redlines 30weight is a really "heavy" 30weight, border line 40 weight but doesn't shear down very much. So if I ran 0w40 pup in it for 5k miles it would be thinner more then likely somewhere between 2-3k mile mark up to 5k then the same 5k mile interval with 5w30 that is more shear stable. At least with redline oil.

Another non gm fun fact. On the Rams with the 5.7 hemi in the past couple years they switched from recommending 5w30 to 0w20. From 09 to now nothing has changed with that motor. It's all to appease the epa and claim .00001 mpg better.

Sorry about the non gm talk. For our 5.3 it will always get 5w30. This last time I picked up 3 5 gallon jugs of pennzoil ultra platinum 5w30 from Walmart for $79. Enough for almost 2 oil changes so I'll order more when needed. Not dexos rated and I could care less if it is or isn't.

Toyota has a 0w8 oil. Pretty soon we will just be filling up our engines right out of the spigot.

 

[Marky Dissod]

From my research the 0w40s especially pennzoil ultra platinum for the 6.4L SRT's (challengers, chargers, ram 2500 and 3500) after a few thousand miles the oil shears down to a 30 weight.
I don't know the scientific reason, other than since it is such wide range going from a 0W (cold) to 40 (hot).
That's based on uoa's from Blackstone I've seen. I run redline 0w30 in the winter and am going to be running redline 5w30 in my 16 6.4L ram.
Redlines 30weight is a really "heavy" 30weight, border line 40 weight but doesn't shear down very much.
So if I ran 0w40 in it for 5k miles it would be thinner, more than likely somewhere between 2-3k mile mark up to 5k, then the same 5k mile interval with 5w30 that is more shear stable. At least with redline oil.

So, you change oil & filter more often than the Oil Life Monitor recommends?

Another non gm fun fact. On the Rams with the 5.7 hemi in the past couple years they switched from recommending 5w30 to 0w20.
From 09 to now, nothing has changed with that motor. It's all to appease the epa and claim .00001 mpg better.

It's to appease the CARB MpG test standards, which get tougher every year, but the sentiment is spot on -
especially since EPA emissions test standards also get tougher every year.

 

[15burban]

So, you change oil & filter more often than the Oil Life Monitor recommends?

All 3 of our vehicles get the oil changed every 5k now. The suburban is the wife's but her previous vehicle was a mitsubishi outlander sport that I was changing every 10k with mobil 1 extended performance. Didn't use or leak any oil from new to 170k when we sold it. My work beater (pontiac g5) I was doing the same 10k but now it's got 263k on it and since about 220k I've switched to 5k intervals on that too since around 5k I need to add some. Since it takes 5 quarts it's just easier to buy a 5 quart jug and change it out and easier to keep track if all the vehicles are on the same schedule.

I don't trust the oil life monitors at all. Granted they're probably a lot better but in my 07 pontiac when I was doing 10k oci I didn't reset it a few times and once it went up to 16k before the monitor actually went off. The biggest thing is that the monitor has no clue what oil is even in the motor.

 

[Marky Dissod]

I don't trust the oil life monitors at all.
Granted they're probably a lot better but in my 07 pontiac when I was doing 10k oci I didn't reset it a few times and once it went up to 16k before the monitor actually went off.
The biggest thing is that the monitor has no clue what oil is even in the motor.

That the Oil Life Monitor has nothing to do with what kind of oil is used, has been known - but not widely disseminated to the general public - since the late '90s when the feature was introduced to the NorthStar & LT1 V8s.
Since the Oil Life Monitor tracks how the driver treats the engine ...
Shall we rename it?
Driver Engine Behaviour Tracker?
Engine Work Rate Counter? (as close a description of what the OLM ACTUALLY does as I can think of)

 

[Antonm]

This explains A LOT.
So far as I'm concerned, this is wh
y I'd use 0W30 or 5W30 instead of 0W20 or 5W20.

(Don't think I drive hard enough to NEED 0W40.)
By the way, what kind of 0W40? I'm not a tribologist, but I know that not every 0W40 is identical to any other 0W40.This is why I asked about the oil specified for the 6.6L L8T, as opposed to the lesser EcoTec V8s that are subject CAFE MpG test standards.

You asked "what kind of 0W40", Mobil 1 Supercar 0W-40 is pretty popular with the new corvette crowd, it's even Dexos rated.

Below is a link to this oil at Summit racing, if you read the description it talks about how that this oil was specifically designed for the Corvette, which as discussed earlier , has the same bearing clearance specs on its 6.2 that the Tahoe/Yukon/ Escalade 6.2 has where GM says run to 0w20.

Pardon Our Interruption

 

[Antonm]

And just because I thought it was funny, I bought an oil fill cap meant for a Corvette that says 0W40 on it.

My original oil fill cap is on the left, new one (thats a genuine GM part), is on the right

Now my Tahoe 6.2 has an oil cap that lists the "wrong" weight oil. Probably confuse a dealer tech if they bothered to actually read it (which they wouldn't).

...

 

[Marky Dissod]

dexos 2 and dexos R - CorvetteForum - Chevrolet Corvette Forum Discussion

C8 Stingray/General Discussion - dexos 2 and dexos R - In a couple of threads, a discussion of oil ratings came up. The 2023 Owners Manual says use engine oils that meet the dexos R specification. The previous 2020-2022 manuals specify dexos 2. All the manuals say see gmdexos.com . That site...

www.corvetteforum.com

GMW18299 (supersedes GM4718M, from the late '90s)

So, not just ANY 0W40 or 5W50.
Need better info ...

 

[Antonm]

dexos 2 and dexos R - CorvetteForum - Chevrolet Corvette Forum Discussion

C8 Stingray/General Discussion - dexos 2 and dexos R - In a couple of threads, a discussion of oil ratings came up. The 2023 Owners Manual says use engine oils that meet the dexos R specification. The previous 2020-2022 manuals specify dexos 2. All the manuals say see gmdexos.com . That site...

www.corvetteforum.com

GMW18299 (supersedes GM4718M, from the late '90s)

So, not just ANY 0W40 or 5W50.
Need better info ...

The new dexos rating has to do with the additive package, specifically the calcium content. Calcium is used as a detergent additive but has been shown to cause pre-ignition detonation in gasoline direct injected engines. Its especially bad on small displacement turbocharged DI engines that build significant boost at low RPM, but it happens on all DI engines to some degree. So the new dexos is just limiting the PPM content of calcium to help stop the pre-ignition problem.

The oil viscosity is the same (or at least in the same range) on EVERY 0w40 oil, it's just the additive package that's different. And since the gasser engines this thread has skewed into talking about aren't forced induction , they really don't benefit from the lower calcium.
...

 

[CTown Duramax]

If you are worried about oil, maybe change the specified 0W20 at shorter intervals. I do mine at 4,000 - 5,000 miles because I think the 0W20 is light and that more frequent changes with city driving could make less wear. GM would have no reason to specify the wrong oil.

 

[BlaineBug]

If you are worried about oil, maybe change the specified 0W20 at shorter intervals. I do mine at 4,000 - 5,000 miles because I think the 0W20 is light and that more frequent changes with city driving could make less wear. GM would have no reason to specify the wrong oil.

That is a good interval.

 

[Antonm]

If you are worried about oil, maybe change the specified 0W20 at shorter intervals. I do mine at 4,000 - 5,000 miles because I think the 0W20 is light and that more frequent changes with city driving could make less wear. GM would have no reason to specify the wrong oil.

You are correct, they absolutely have a reason for specifying the oil they do,,,,and that reason is CAFE and regulatory requirements.

Their reasoning has absolutely nothing to do with it being the best oil for engine longevity.
...