BREAKING: GM is officially recalling the L87

[KMeloney]

When I went to pick up my ‘23 Denali after the passed test, there was a tech standing around the service desk, so I got to taking to him about the recall and whatnot. There were some interesting takeaways:

- He said he’s seen trucks pass the PICO test and then fail later (I haven’t heard of any post-test/post heavier oil failures)

- He hadn’t seen any ‘25 6.2s fail, but said he’s seen ‘25 “baby diesels” (the 3.0) fail now

- He believes that the failures are due to faulty materials (bad metallurgy — not machined-out-of-spec parts per se), and since parts are “globally sourced” by various brands, it’s why Toyota and other manufacturers are having problems, too

- Engines are taking 2 weeks to get now, whereas they initially had a truck in for 8 months waiting for a new engine

- He believes that the failure rate on the 6.2s is much higher than 3-5%

Not all new/earth-shattering stuff, but this guy frequents a techs forum where all of this stuff is discussed, and so I felt like I was getting some good feedback from a hands-on mechanic’s perspective.

I’m still optimistic about my truck (maybe moreso after the test). I noticed no change in how the truck drives with the heavier oil in it (might have felt smoother, even), so I’m pretty happy.

 

[Lonny]

Has anyone noticed a decrease in acceleration performance after an upgrade to the new oil? Can’t tell if it is real or imagined!

 

[Stbentoak]

- He hadn’t seen any ‘25 6.2s fail, but said he’s seen ‘25 “baby diesels” (the 3.0) fail now

I'm on two or three diesel forums that specifically cover the 3.0 Duramax. There hasn't been any real talk of increasing LZ0 failures that I'm aware of. Sure, there are a few here or there... but nowhere near a predictable or trackable rate. Most are tracked to poor assembly of a certain component....

 

[Scarey]

Slight thread bend. I’m a ‘25 Tahoe babymax. I’m interested in finding some 3.0 forums, can you share which forums you track?

 

[jfoj]

Has anyone noticed a decrease in acceleration performance after an upgrade to the new oil? Can’t tell if it is real or imagined!

No change in anything should be detected unless GM is reflashing the ECU, I went to 0W40 on my 2024 at 544 miles and have not looked back. This along with a DFM/ASS defeat I still get 20+ MPG on the highway driving pretty hard.

If you do a lot of highway driving, these engines shear the oil to the point that is tends to be just below the threshold for the stated viscosity rating in as few as 2000 miles.

I have seen this on my vehicle and others that have a high amount of highway usage.

 

[CommodoreSS]

Something else besides programming and shift points and oil is adrift. 6.2 is in the 2020 pickups, with the 10L80 and the DFM. Those weren’t in the recall or the blowing rod bearings or crank bearings lore…

Umm, I beg to differ. I own a 2020 Silverado HighCountry with the 6.2 and 10 speed trans. It had catastrophic lifter failure @ 70k miles. It had been to the dealer several times for a louder than what I thought was normal valve train noise and all they did was replace the accessory drive pulleys and tensioner. Eventually it left chunks of metal in the oil pan but it did drive to the dealer amazingly. I’m lucky I got the extended warranty but with the national back ordered engine rpo it took months to get it back. GM has left a lot of people holding the bag on this one. It cost me $500. I’m lucky though, that bill could’ve been $12k.

 

[Vladimir2306]

No change in anything should be detected unless GM is reflashing the ECU, I went to 0W40 on my 2024 at 544 miles and have not looked back. This along with a DFM/ASS defeat I still get 20+ MPG on the highway driving pretty hard.

If you do a lot of highway driving, these engines shear the oil to the point that is tends to be just below the threshold for the stated viscosity rating in as few as 2000 miles.

I have seen this on my vehicle and others that have a high amount of highway usage.

Don't write nonsense, nothing liquefies there. I posted an oil test of 0-20, on a mileage of 10.000 km, and I drive a lot very fast on the highway. The oil has the original viscosity.

 

[Stbentoak]

Slight thread bend. I’m a ‘25 Tahoe babymax. I’m interested in finding some 3.0 forums, can you share which forums you track?

The main one is Duramax Diesel forum which I am a member. I believe it is a sister forum to this site... There are others that I peruse but I am not members of. So, if there's a hot topic going on I just see if it jumps up a few other places. Many times, when somebody screams about an issue. It's only about their issue... When I see it boiling up on other sites. Then I know that it could be a real issue..

 

[jfoj]

Don't write nonsense, nothing liquefies there. I posted an oil test of 0-20, on a mileage of 10.000 km, and I drive a lot very fast on the highway. The oil has the original viscosity.

Vladimir,

You just keep jumping to unfounded conclusions. You should stop trying to tell me I do not know what I am talking about. I have many data points that clearly show there is a viscosity shearing problem under specific driving conditions which are VERY different than your driving conditions in Russia. You clearly do not understand under what operating conditions oil shear will occur. Here in the US most drivers cannot and do not drive much more than 75 MPH for long periods of time, they may be able to exceed this for short periods, but typically here in the US depending on where you live and the traffic congestion, you are lucky to be able to travel at more than 70 MPH for long periods of time. Under these circumstances there is Low RPM, High Loading on the the 6.2l the way the TCM is programmed.

I have MULTIPLE oil analysis from different oils and different vehicles that clearly show the 6.2l bearing loading is shearing the oil down below the bottom edge of the viscosity range or window when driven on the highway typically under 1700 RPM. This is occurring in and around 2000 miles. This is also not due to fuel dilution.

I would love to have seen multiple oil samples from failed 6.2l with 0W20 oil to see what the viscosity was when the engines failed. I think this would be a real eye opener or many people.

 

[Vladimir2306]

Vladimir,

You just keep jumping to unfounded conclusions. You should stop trying to tell me I do not know what I am talking about. I have many data points that clearly show there is a viscosity shearing problem under specific driving conditions which are VERY different than your driving conditions in Russia. You clearly do not understand under what operating conditions oil shear will occur. Here in the US most drivers cannot and do not drive much more than 75 MPH for long periods of time, they may be able to exceed this for short periods, but typically here in the US depending on where you live and the traffic congestion, you are lucky to be able to travel at more than 70 MPH for long periods of time. Under these circumstances there is Low RPM, High Loading on the the 6.2l the way the TCM is programmed.

I have MULTIPLE oil analysis from different oils and different vehicles that clearly show the 6.2l bearing loading is shearing the oil down below the bottom edge of the viscosity range or window when driven on the highway typically under 1700 RPM. This is occurring in and around 2000 miles. This is also not due to fuel dilution.

Yes, you don't know what you're talking about, and you're confusing people. When driving on the highway, even at a speed of 70 miles per hour, at least for 20-30 minutes, the engine will be warmed up so much that the fuel from the oil will immediately evaporate. fuel dilution of oil occurs only during short trips in urban areas, when the engine does not have time to warm up, and the fuel mixture is saturated. If you have an oil analysis where oil 0-20, or 0-40, has a viscosity shift, then post it. My 0-20 oil analysis, with a mileage of 6.250 miles, shows that the oil retains its viscosity according to the 0-20 oil parameters, even with 2.2% fuel in the oil.

 

[Mma-007]

Something for people to keep an eye out on when you take your rig in. My rig passed two weeks ago. According to them they changed the oil to 0w-40. I decided to do an oil change (I prefer 5w30 in my rig). I feel my rig runs better with said oil. Maybe it’s a placebo effect but I can notice it’s much quieter when I accelerate and idle. Anyways, when I drained the supposed 0w-40 oil. It was black as charcoal. Likelyhood they didn’t change my oil and said they did. Correct me if I’m wrong but I thought 0w-40 oil was synthetic and yellow? Can anyone confirm?

 

[homesick]

Something for people to keep an eye out on when you take your rig in. My rig passed two weeks ago. According to them they changed the oil to 0w-40. I decided to do an oil change (I prefer 5w30 in my rig). I feel my rig runs better with said oil. Maybe it’s a placebo effect but I can notice it’s much quieter when I accelerate and idle. Anyways, when I drained the supposed 0w-40 oil. It was black as charcoal. Likelyhood they didn’t change my oil and said they did. Correct me if I’m wrong but I thought 0w-40 oil was synthetic and yellow? Can anyone confirm?

If they didn't change the oil, doesn't that mean that YOU let it get nasty?

joe

 

[Vladimir2306]

Something for people to keep an eye out on when you take your rig in. My rig passed two weeks ago. According to them they changed the oil to 0w-40. I decided to do an oil change (I prefer 5w30 in my rig). I feel my rig runs better with said oil. Maybe it’s a placebo effect but I can notice it’s much quieter when I accelerate and idle. Anyways, when I drained the supposed 0w-40 oil. It was black as charcoal. Likelyhood they didn’t change my oil and said they did. Correct me if I’m wrong but I thought 0w-40 oil was synthetic and yellow? Can anyone confirm?

It depends on how many miles have passed since the oil change. Generally, blackening of the oil after 700 miles is completely normal. It means the oil is working to clean the engine.

 

[James Fagin]

Has anyone noticed a decrease in acceleration performance after an upgrade to the new oil? Can’t tell if it is real or imagined!

Mine seems to be better or the same I can't tell but my acceleration is still great after the new oil and its been two months now.

 

[BigdawgR6]

I'm dropping my rig back off tomorrow since it's been idling weird after the new oil. Hopefully they can figure it out and not say it's normal.

 

[LewL]

Any issues with the 2025 6.2s or has the 2025 correction worked?

 

[Vladimir2306]

Any issues with the 2025 6.2s or has the 2025 correction worked?

Unfortunately, nothing has changed. The 2025 6.2 engines still break down the same way, and several opened 2025 engines have shown that there are no changes compared to the 2021-2024 6.2 engines.

 

[zbad55]

Any issues with the 2025 6.2s or has the 2025 correction worked?

The issues with the incorrectly machined crankshafts has been corrected for the late 24 models and for 25 models. There has not been any indication of engine failures.

 

[Vladimir2306]

The issues with the incorrectly machined crankshafts has been corrected for the late 24 models and for 25 models. There has not been any indication of engine failures.

Could you clarify how exactly the 2024-2025 issues were addressed? According to our data, the 2021-2024 and 2024-2025 crankshafts are absolutely identical. Moreover, we even had the shafts' hardness analyzed; the journal area is as hard as a regular nail, and it's not heat-treated.

 

[Vladimir2306]

The issues with the incorrectly machined crankshafts has been corrected for the late 24 models and for 25 models. There has not been any indication of engine failures.

It's funny, apparently all the defective 2025s with a 6.2 engine went to Russia. Several service centers have already posted several dozen 2025 cars here, and the problems are still the same: bearing scuffing, crankshaft rotation, engine seizure.