L87 6.2: “NHTSA to investigate potential for engine failure in nearly 1 million GM trucks, SUVs”

[Stbentoak]

In today's modern manufacturing, there is no excuse for cleaning out chips, debris, or FOD (That's what they call it in the aircraft manufacturing world..) As someone who has worked in the aircraft engine industry. this would get you disqualified as a supplier immediately. 2 main things....foreign objects and parts that are out of tolerance. More than one instance of this and you are out. Evidently this criterion doesn't apply with automotive suppliers or GM's internal manufacturing.....

 

[jfoj]

While debris may be an issue with these engines, the oiling system is really in question. The 6.2l uses the same basic oiling system as the 6.0l non AFM/DFM engine and it was rock solid. My 20 year old 6.0l has 275k miles on it without the engine ever being opened up. Minimal mainteance and still going strong.

I think where GM went sideways on the 6.2l is they added 2 stage oil pump to reduce oil pressure under lower loads to save fuel along with the 0W20 engine oil. My 2005 6.0l has used 5W30 for 275k without a problem. Then they went from AFM which could control 4 cylinders to DFM which could control up to 7 cylinders at a time. The problem is the AFM requires oil pressure and volume to control the lifters, this oil pressure and volume is basically tanken away from the main bearings, so you can end up with oil starvation for the main bearings, especially the front main bearing which is the absolutely last thing lubricated in the oiling path.

I can see where DFM disabling can and provably will help these engines last longer, not sure if the oil pump could be fixed in the higher pressure mode without causing other problems, with the DFM and/or triggering a CEL. Maybe a spoof for the high pressure stage of the oil pump could be employed somehow?

After a lot of research it appears the front main and rod #1 & #2 are probably the most common failures, however, there have been #3 main/thrust failures and I have also seen rear main failures. Additionally I have seen many pistons destroyed and rods bent or breach the block. So there are an number of failure modes, probably nobody at the dealers or GM has really tracked the failures.

Seeing 2 basic issues here, possible contamination, or just plain oiling problems that lead to contamination as bearings and other parts start to come apart.

5.3l seem to have less problems, they do not have the 2 stage oil pump, they just have a variable displacement oil pump from my research. I have seen many 5.3l with lifter problems, not so many with bearing failures. But this is just what I have been able to find online and there are probably many failures that have not been documented online .

 

[flajax]

I have a 2021 with 55k miles on it, has anyone done a blackstone oil analysis on a higher mileage engine to see if there's anything out of the ordinary prior to failure? I'm in FL, and have avoided the 0w20 oil; hell might go change it again today and send some over to blackstone.

 

[CMoore711]

I have just submitted all my info to the NHTSA.

I think this is the best thing any GM SUV owner with a 6.2L L87 that has experienced engine failure can do. Submit your experience and vehicle details to the NHTSA. Not sure what that process looks like or includes; I'm sure it might take some time, effort, and documentation.

Whether you still own the vehicle or not.
Whether GM repaired your vehicle with a new engine replacement or not.

Being proactive and providing more information to the NHTSA could influence/impact the NHTSA to force GM's hand to admit they have a problem, develop an actual solution, and implement the corrective action on GM's dime.

 

[MattAlaska]

I think this is the best thing any GM SUV owner with a 6.2L L87 that has experienced engine failure can do. Submit your experience and vehicle details to the NHTSA. Not sure what that process looks like or includes; I'm sure it might take some time, effort, and documentation.

Whether you still own the vehicle or not.
Whether GM repaired your vehicle with a new engine replacement or not.

Being proactive and providing more information to the NHTSA could influence/impact the NHTSA to force GM's hand to admit they have a problem, develop an actual solution, and implement the corrective action on GM's dime.

It's actually much easier than I expected. Definitely recommend.

 

[blanchard7684]

Being proactive and providing more information to the NHTSA could influence/impact the NHTSA to force GM's hand to admit they have a problem, develop an actual solution, and implement the corrective action on GM's dime.

You'd think the warranty costs, buy-backs, and lemon-law action would be enough.

 

[blanchard7684]

Seeing 2 basic issues here, possible contamination, or just plain oiling problems that lead to contamination as bearings and other parts start to come apart.

5.3l seem to have less problems, they do not have the 2 stage oil pump, they just have a variable displacement oil pump from my research. I have seen many 5.3l with lifter problems, not so many with bearing failures. But this is just what I have been able to find online and there are probably many failures that have not been documented online .

I think this is accurate.

The failed bearings I've seen so far look like contamination or a light to moderate oil starvation. Both can look similar on failed journal bearings for basically the same reason--deterioration of oil film integrity.

The oil flow diagrams you've linked to are helpful as well. It does show that the #1 and #2 mains could be more susceptible for damage from loss of pressure.

If a 2 stage pump is glitchy switching between stages it could cause a momentary drop in system pressure (how much of a drop, who knows?). it may also cause a miss timed switch event on lifters. I wonder what the correlation is between failed rod and main bearings and damage on lifters and cam?

5.3 and 6.2 have different oil pump part numbers so I can believe they would be different pumps.

 

[jerry455]

I am using Mobil 1 0W30.

 

[B-train]

Below is first oil change from ‘24 5.3… iron and aluminum in the bottom of my drain bucket… if you at it you can see it.. i think drain - a couple anyway before 1500 miles.

I still am thinking a drop in cleaning or suppliers.. of the rocker or lifters.. there is just no way you want to run that oil for 7500 miles.. yikes!! There is a lot of boring and tapping going on.. to build the block. It might be cleaning is less..

Or, it might be a brilliant plan to piss people off about V8 engines so they will more easily swallow the 4 or 6 cylinder pill GM had been wanting people to accept(?????)

 

[RG23RST]

Both the L84 & L87/L8T pumps have a high stage and low stage so they aren't that different in some respects. They aren't interchangeable though. The pumps are high volume to offset the lower relative viscosity of the oil. There isn't any functional difference between a 0w20 at the high end of the API spec and a 5w30 at the low end of its spec. Oil pressure is controlled via the ECM and oil pump control solenoid on both. L8T doesn't have the bottom end problems as the 6.2 does. It's been a supplier issue is my understanding with the bearings.

0w20 oil isn't going to hurt the engines but I have run 5w30 in mine during summer for no other reason than it was on the shelf and 0w20 wasn't that day for whatever reason. Some say the valvetrain is quieter on Xw30 oils so YMMV. After 60K miles I'll swap this one over fully to 5w30 just like I did the last one but you do you.

 

[RG23RST]

I think this is accurate.

The failed bearings I've seen so far look like contamination or a light to moderate oil starvation. Both can look similar on failed journal bearings for basically the same reason--deterioration of oil film integrity.

The oil flow diagrams you've linked to are helpful as well. It does show that the #1 and #2 mains could be more susceptible for damage from loss of pressure.

If a 2 stage pump is glitchy switching between stages it could cause a momentary drop in system pressure (how much of a drop, who knows?). it may also cause a miss timed switch event on lifters. I wonder what the correlation is between failed rod and main bearings and damage on lifters and cam?

5.3 and 6.2 have different oil pump part numbers so I can believe they would be different pumps.

This problem didn't exist before MY21 on the L87. It's not an oiling issue. The 5.3 and 6.6 would suffer the same fate if it was because they're the same design. Even with the oil control solenoid commanding "low" pressure it's still anywhere from 20-48psi or thereabout. Get on the gas and into high RPM the solenoid will command higher pressure up to 80psi or so.

I don't have any inside information so just speculation but I'm curious if the failed 6.2 engines came from Tonawanda or Spring Hill. Spring Hill had a bad batch of 5.3s get out that were put on stop sale. The out of spec lifter bore issue also came from Spring Hill.

 

[RG23RST]

In today's modern manufacturing, there is no excuse for cleaning out chips, debris, or FOD (That's what they call it in the aircraft manufacturing world..) As someone who has worked in the aircraft engine industry. this would get you disqualified as a supplier immediately. 2 main things....foreign objects and parts that are out of tolerance. More than one instance of this and you are out. Evidently this criterion doesn't apply with automotive suppliers or GM's internal manufacturing.....

Aircraft engines aren't produced by the millions though. Any mass produced engine is going to "make metal" more than a low volume engine sold at high enough price to warrant more specialized manufacturing and preparation.

 

[PPK_]

This problem didn't exist before MY21 on the L87. It's not an oiling issue. The 5.3 and 6.6 would suffer the same fate if it was because they're the same design. Even with the oil control solenoid commanding "low" pressure it's still anywhere from 20-48psi or thereabout. Get on the gas and into high RPM the solenoid will command higher pressure up to 80psi or so.

I don't have any inside information so just speculation but I'm curious if the failed 6.2 engines came from Tonawanda or Spring Hill. Spring Hill had a bad batch of 5.3s get out that were put on stop sale. The out of spec lifter bore issue also came from Spring Hill.

I have had a 5.3 from ny and one from mexico… i did not know spring hill made them too… i do agree one site might a problem in assembly..

 

[blanchard7684]

This problem didn't exist before MY21 on the L87. It's not an oiling issue. The 5.3 and 6.6 would suffer the same fate if it was because they're the same design. Even with the oil control solenoid commanding "low" pressure it's still anywhere from 20-48psi or thereabout. Get on the gas and into high RPM the solenoid will command higher pressure up to 80psi or so.

I don't have any inside information so just speculation but I'm curious if the failed 6.2 engines came from Tonawanda or Spring Hill. Spring Hill had a bad batch of 5.3s get out that were put on stop sale. The out of spec lifter bore issue also came from Spring Hill.

Good info thanks.

 

[Stbentoak]

Aircraft engines aren't produced by the millions though. Any mass produced engine is going to "make metal" more than a low volume engine sold at high enough price to warrant more specialized manufacturing and preparation.

Whether you build one or one million, that doesn't matter to the person that got that one bad one. I've worked in high volume atmospheres and unless you adopt the philosophy of, we will make them "Right 1st, and Fast 2nd" your business is doomed to die a slow death.

 

[blanchard7684]

This problem didn't exist before MY21 on the L87. It's not an oiling issue. The 5.3 and 6.6 would suffer the same fate if it was because they're the same design. Even with the oil control solenoid commanding "low" pressure it's still anywhere from 20-48psi or thereabout. Get on the gas and into high RPM the solenoid will command higher pressure up to 80psi or so.

I don't have any inside information so just speculation but I'm curious if the failed 6.2 engines came from Tonawanda or Spring Hill. Spring Hill had a bad batch of 5.3s get out that were put on stop sale. The out of spec lifter bore issue also came from Spring Hill.

A follow up on this.

My understanding is 5.3 has a single stage oil pump vs a 2 stage on 6.2. Edit: looks like the l83 does have two stage oil pump.

It also looks like part numbers changed on 6.2 oil pumps. For instance a 2019 oil pump is a 12686433 part number vs 2024 is 12733670.

(5.3 oil pump part number is 12733671 across same time frame)

Oil control solenoid stayed with same part number over same time frame (12686431) on 6.2.

 

[PPK_]

A follow up on this.

My understanding is 5.3 has a single stage oil pump vs a 2 stage on 6.2. Edit: looks like the l83 does have two stage oil pump.

It also looks like part numbers changed on 6.2 oil pumps. For instance a 2019 oil pump is a 12686433 part number vs 2024 is 12733670.

(5.3 oil pump part number is 12733671 across same time frame)

Oil control solenoid stayed with same part number over same time frame (12686431) on 6.2.

Is the oil pressure sensor near pump the or at the end of the what journals and cam lifters that are oiled? I mean each journal as you go away from the is going to have less pressure..

 

[blanchard7684]

Is the oil pressure sensor near pump the or at the end of the what journals and cam lifters that are oiled? I mean each journal as you go away from the is going to have less pressure..

The solenoids are in different locations.

 

[jfoj]

Is the oil pressure sensor near pump the or at the end of the what journals and cam lifters that are oiled? I mean each journal as you go away from the is going to have less pressure..

From the diagrams it appears the oil pressure sensor is mounted on the rear of the DFM manifold that is on top of the engine. So in this case the sensor is at the beginning of the oil flow path which is typical of most engines, but with all the DFM gear and the 2 stage oil pump, it would have probably been wiser to have the oil pressure sensor at the end of the oiling path.

This is what happens when you take a basic 60+ year old design and just keep adding bits and pieces on it over the years.

For reference I was able to obtain oil pressure values using a more advanced scan tool.

Approximately 28 PSI warm idle in gear
Approximately 33 PSI warm idle in neutral
Approximately 46 PSI @ 75 MPH at approximately 1600 RPM

The oil pressure did appear to boost past the 1/2 way point on the dash gauge when passing and the RPMs were up. Hopefully I will be able to graph the oil pressure behavior so I can get a better idea how it is controlled.

 

[jfoj]

GM's Broken 6.2L V8s Are Stranding Owners for Weeks as Replacement Engine Pipeline Dries Up

The situation has left dealers struggling to source new engines and owners with no clear repair timelines, and it's especially dire for people who need their trucks for work.

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