Engine Failure

[MookdocOE]

Oil was absolutely a contributing factor. Don't take it from me, take it from an expert:

I am about as a big of fan as you are of 0W-20 I just find it interesting that GM replaces the motors with 0W-20

 

[BimmerFan]

I am about as a big of fan as you are of 0W-20 I just find it interesting that GM replaces the motors with 0W-20

I wonder if this is an EPA thing. The cars/trucks engine configuration has to pass EPA tests for emissions and fuel economy. The water-like 0W20 probably contributes to the mileage ratings (why else would you use it?) so GM sticks with it rather than spending millions to recertify/test/measure the EPA stuff.

I'm just guessing here.

 

[ngoni]

I wonder if this is an EPA thing. The cars/trucks engine configuration has to pass EPA tests for emissions and fuel economy. The water-like 0W20 probably contributes to the mileage ratings (why else would you use it?) so GM sticks with it rather than spending millions to recertify/test/measure the EPA stuff.

I'm just guessing here.

You're probably on to something. GM likely doesn't want to pay to get the entire fleet retested with 0W-40 as standard even though 0W-20 contributed to a ton of engine failures.

 

[668LT4]

Lol I'm that guy... it's not a comprehensive list of all the failures, just the ones reported on this forum. If we go for the number you estimated, 50 motors out of every 6000, that actually is really not great from a modern manufacturing quality point of view.

The reason I made the comment is that from the outside looking in, the failure mode reported for our LT4 looks remarkably similar to the issues with the L87. Hard to say if the defects are parts or designs in common between the engines or if it's just a coincidence. I'm not buying the explanation that the failures are due to drivers breaking in their cars incorrectly though.

I'm not getting my knickers in a twist over it, I'll just get the extended warranty and continue enjoying my car, even, dare I say it, redlining it often!

I agree, 50 seems like a lot. But at this rate, 99/100 LT4 Blackwing owners will never have a problem.

I thought this video was quite informative. He mentions the importance of break-in. Everyone has their own belief, I just don't see redlining a new motor at 12 miles as a good idea. I agree it can't be the reason for all 50 failures, but as this guy states, "the highest amount of wear is during engine break-in".

I am only 7 months into ownership of my 2024. I will hit the powertrain years before miles on my warranty. If GM determines the LT4 has a catastrophic flaw in the next 5+ years, I'll happily take a brand new engine if mine blows.

 

[jbawden]

TMOG is a big fan of changing the factory oil before 1,000 miles. He mentions it again in the video above. Interesting comments about viscosity.

 

[MookdocOE]

I wonder if this is an EPA thing. The cars/trucks engine configuration has to pass EPA tests for emissions and fuel economy. The water-like 0W20 probably contributes to the mileage ratings (why else would you use it?) so GM sticks with it rather than spending millions to recertify/test/measure the EPA stuff.

I'm just guessing here.

Yup, your probably correct! It's always about the money......

 

[ngoni]

I am about as a big of fan as you are of 0W-20 I just find it interesting that GM replaces the motors with 0W-20

Yeah this blog post goes into more detail. Apparently the 0W-40 is just for engines that are at risk due to contamination or manufacturing defects.

https://gmauthority.com/blog/2025/05/should-you-use-0w-40-oil-in-your-non-recalled-gm-6-2l-l87-engine/

 

[MookdocOE]

Yeah this blog post goes into more detail. Apparently the 0W-40 is just for engines that are at risk due to contamination or manufacturing defects.

https://gmauthority.com/blog/2025/05/should-you-use-0w-40-oil-in-your-non-recalled-gm-6-2l-l87-engine/

Toyota it appears to be filling cars with 0W-8 Just when you thought to have seen it all.....

 

[Deneed4spd]

Toyota it appears to be filling cars with 0W-8 Just when you thought to have seen it all.....

My bmw x5 now is 0w-12. It continues to go lower.

 

[MookdocOE]

My bmw x5 now is 0w-12. It continues to go lower.

Ridiculous imo 0W-20 is as far as I can go?