NHTSA opens preliminary probe into more than 870,000 GM vehicles

[Jay P Wy]

Interesting video.

763K views · 11K reactions | It Blew up at 4 Miles! Part failure or assembly error? GMC 6.2L #enginebuilding #EngineRepair #autoshop #autorepair | Dave's Engines

It Blew up at 4 Miles! Part failure or assembly error? GMC 6.2L #enginebuilding #EngineRepair #autoshop #autorepair.

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Another video on the same motor. Broken piston where the c-clip should be. I'm not making any links to this and all the other 6.2l failures just worth a look.

5.4K views · 96 reactions | GM L87 Connecting Rod Failure. It’s Not a Bad Bearing | Dave's Auto Center

GM L87 Connecting Rod Failure. It’s Not a Bad Bearing.

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[Sean Michael]

I'm not experienced with engine building, but I watched that video when it came out and a lot of commenters on the video were saying it apeared to have already been rebuilt because of the presence of a heat tab, it had too much carbon build-up to have only been a 4-mile engine, and the fact Dave's garage even got it, because a stock engine that failed would've gone back to GM. I don't know who to believe, but some of the skepticism around that particular engine seemed believable to me.

 

[Jay P Wy]

I'm not experienced with engine building, but I watched that video when it came out and a lot of commenters on the video were saying it apeared to have already been rebuilt because of the presence of a heat tab, it had too much carbon build-up to have only been a 4-mile engine, and the fact Dave's garage even got it, because a stock engine that failed would've gone back to GM. I don't know who to believe, but some of the skepticism around that particular engine seemed believable to me.

I agree. I have lots of skepticism about that engine and the circumstances around how Dave's shop got it and why it's not at a dealer. Makes me wonder if the damage to the area around the c-clip was there before it was put together.

 

[seatown]

That would be shady if they were “planting” lies.

That metal looks pretty clean and new though.

If they’re be honest that it was a 4 mile engine, it looks like bad QA at the factory.

 

[Antonm]

Unless the owner of the vehicle just decided to eat the cost and not have the engine replaced under warranty, there is NO WAY that engine would not have gone back to GM,,, no way.

So unless YouTube is paying $30k for a video, we’re probably getting lied to. It may be a lie of omission , like “oh yeah, this engine has been rebuilt once before, or this vehicle was a theft recovery ” type thing that they didn’t bother to mention , but again, unless the owner just said “ this is fine, I don’t want you to fix it under warranty “ we’re not getting the full story.
…

 

[RG23RST]

That would be shady if they were “planting” lies.

That metal looks pretty clean and new though.

If they’re be honest that it was a 4 mile engine, it looks like bad QA at the factory.

That engine is a reman unit.

I work at a dealer and have seen a few 6.2s disassembled onsite. Never seen an issue with wrist pin clips but have seen the piston in the oil pan after the connecting rod snapped. When the bearings gall some people keep on truckin' until it locks up at a stoplight or catastrophically fails. One I remember the crank got so hot from a spun #2 main it had blueing along with missing most of the rod bearings on that journal. Most people DGAF and drive it until it quits.

 

[RG23RST]

Everything we've been told at the dealership level (which ain't much) points to a bearing supplier issue. Assembly QA problems can always slip through but that would be VERY rare. I have a relative that works at Spring Hill and he tells me almost every machined surface is checked 2 or 3 times by either go/no go gauges and robotic measuring. Most of the engine assembly is actually done robotically as well and they get a spin-up on a giant electric motor to check for function and assembly errors. It seems implausible that a factory error could continue for more than a few dozen or tens of dozens of units before being caught. Modern automation and quality processes are unbelievable.

The issue of oversized lifter bores was not a blanket issue for MY23. It was a limited number. Same deal for the L84 with machining debris it was not that many. What's happening to the L87 is something else entirely.

 

[jfoj]

The testing of engines after being built is called "Cold Testing" where a large electric motor is used to sping the engine at different RPM's and look for specific parameters. They can monitor the torque required turn the engine, the airflow thru the engine, monitor for noise and vibrations and so forth. I and not sure if GM used the Spintron or something similar.

Except forf the few broken connecting rods and broken or wedged pistons, the majority the problems are all bearings failing and/or spinning. The bearing supplier issue should have sailed in 2021 or by mid 2022. But we are here in early 2025 and still seeing the 2023 and 2024 models with problems. Waiting on the first 2025 problems to surface soon.

Seems to be a subset that fail before the first oil change, typically before 7500 miles, a few in the 10,000-15,000 window then again in the 25,000-35,000 window. Not sure what is really causing the different failure windows.

I really belive the 6.2l is a perfect storm of a number of problems. Some based on design choices, some due to the programming of the ECM/TCM, some are on how the vehiles are loaded and used, some are problems caused (I have to be careful with this term, but I do ot have a better one) by how the vehicle is used buy the owner, what fuel they put in the tank, how much remote starting or allowing the egine to warm up without driving, oil change intervals which are typically following the OLM, but in many cases this is too late for how the vehicle is being used.

The 6.2l behaves like a Diesel and is put under tremdous Torque loading at Low RPM. On the highway most of these engines do not turn more than 1700-1800 RPM, the transmission rarely downshifts. The bearings may be getting beat out of these engines?

Seems that every one of the bottom end failures is pretty much caused by lack of lubrication, not enough lubrication or contaminated lubrication.

I am going to go out on an limb and call what is going to happen with this NHTSA investigation.

I could be very wrong about this, but here it goes:

GM is either going to somehow show the numbers are not that high or that the problems have all occurred and they are now tapering down to a safe and managable number.

I do not expect there to be a recall where engines are replaced.

I expect that GM will have a recall offering a software solution to hardware failures. They will also probably print up some updated requirements or reinforced requirments that may not have been followed by owners regularly.

1. GM will REQUIRE the 6.2l to use Preminum fuel
2. GM will suggest that then engines not be remote started or started and allow to idle to warm up
3. GM will instruct that the engine oil be checked ever 3rd to 4th fill up and topped off, not waiting until the low oil light is illuminated
4. GM will likely extend the engine warranty to 10 years/150,000 miles
5. GM will likely reprogram the OLM for a shorter oil change intervals
6. GM will likely reporgram the 2 stage oil pump to either run at full pressure all the time, or switch the 2nd higher pressure stage on earlier and under specific circumstances, like when the oil pressure drops to 20 PSI or lower.
7. GM will likely reprogram the oil pressure warning to come on when the oil pressure drops to a specific low level or possibly have a low pressure trend that triggers a dash warning that indicates there is a low oil pressure situation and you should exit the road.
8. GM will likely implement a "Limp Mode" if the oil pressure drops to a dangerously low value to hopefully allow the vehicle to be pulled off the road before the engine siezess.
9. GM may reconfigure/recalibrate the towing mode, most likely alter transission shift points, may limit the top 1-3 gears, may alter the oil pump stage tirgger point when towing. May even state the engine oil be changed after towing or implement some torque counter that adjust the oil change interval
10. GM may make a change on the oil requirement for either daily driving and/or towing

So we shall see what and when anything happens. I expect that I may be correct on some of the action GM will take. I am not expecting any answers until late 2025 or early 2026. So if you own a 6.2l I would not hold my breath for a great and permenant solution.

 

[Vladimir2306]

The testing of engines after being built is called "Cold Testing" where a large electric motor is used to sping the engine at different RPM's and look for specific parameters. They can monitor the torque required turn the engine, the airflow thru the engine, monitor for noise and vibrations and so forth. I and not sure if GM used the Spintron or something similar.

Except forf the few broken connecting rods and broken or wedged pistons, the majority the problems are all bearings failing and/or spinning. The bearing supplier issue should have sailed in 2021 or by mid 2022. But we are here in early 2025 and still seeing the 2023 and 2024 models with problems. Waiting on the first 2025 problems to surface soon.

Seems to be a subset that fail before the first oil change, typically before 7500 miles, a few in the 10,000-15,000 window then again in the 25,000-35,000 window. Not sure what is really causing the different failure windows.

I really belive the 6.2l is a perfect storm of a number of problems. Some based on design choices, some due to the programming of the ECM/TCM, some are on how the vehiles are loaded and used, some are problems caused (I have to be careful with this term, but I do ot have a better one) by how the vehicle is used buy the owner, what fuel they put in the tank, how much remote starting or allowing the egine to warm up without driving, oil change intervals which are typically following the OLM, but in many cases this is too late for how the vehicle is being used.

The 6.2l behaves like a Diesel and is put under tremdous Torque loading at Low RPM. On the highway most of these engines do not turn more than 1700-1800 RPM, the transmission rarely downshifts. The bearings may be getting beat out of these engines?

Seems that every one of the bottom end failures is pretty much caused by lack of lubrication, not enough lubrication or contaminated lubrication.

I am going to go out on an limb and call what is going to happen with this NHTSA investigation.

I could be very wrong about this, but here it goes:

GM is either going to somehow show the numbers are not that high or that the problems have all occurred and they are now tapering down to a safe and managable number.

I do not expect there to be a recall where engines are replaced.

I expect that GM will have a recall offering a software solution to hardware failures. They will also probably print up some updated requirements or reinforced requirments that may not have been followed by owners regularly.

1. GM will REQUIRE the 6.2l to use Preminum fuel
2. GM will suggest that then engines not be remote started or started and allow to idle to warm up
3. GM will instruct that the engine oil be checked ever 3rd to 4th fill up and topped off, not waiting until the low oil light is illuminated
4. GM will likely extend the engine warranty to 10 years/150,000 miles
5. GM will likely reprogram the OLM for a shorter oil change intervals
6. GM will likely reporgram the 2 stage oil pump to either run at full pressure all the time, or switch the 2nd higher pressure stage on earlier and under specific circumstances, like when the oil pressure drops to 20 PSI or lower.
7. GM will likely reprogram the oil pressure warning to come on when the oil pressure drops to a specific low level or possibly have a low pressure trend that triggers a dash warning that indicates there is a low oil pressure situation and you should exit the road.
8. GM will likely implement a "Limp Mode" if the oil pressure drops to a dangerously low value to hopefully allow the vehicle to be pulled off the road before the engine siezess.
9. GM may reconfigure/recalibrate the towing mode, most likely alter transission shift points, may limit the top 1-3 gears, may alter the oil pump stage tirgger point when towing. May even state the engine oil be changed after towing or implement some torque counter that adjust the oil change interval
10. GM may make a change on the oil requirement for either daily driving and/or towing

So we shall see what and when anything happens. I expect that I may be correct on some of the action GM will take. I am not expecting any answers until late 2025 or early 2026. So if you own a 6.2l I would not hold my breath for a great and permenant solution.

Cold testing is also very interesting. We discussed it with the guys from the service. I wrote above that they now disassemble engines straight out of the box. Judging by the condition it is in, it seems like there is no cold testing at GM. Moreover, we have several people in our group who bought a car with a 6.2 engine and immediately noticed a metal chip on the oil dipstick when checking the oil level.
Next, both of them had their oil changed, the filter was cut and it was literally clogged with metal pieces. It was literally 2-3 thousand km. After which they carried out maintenance and began to observe, and this did not happen again. It seems that there is no cold testing, or cold running-in as we call it, at GM, or they have stopped doing it, and in fact, the engines are already run-in on the car.

 

[the 18th letter]

If warming a car up is causing an engine to fail in less than 30k miles I don’t think there is a fix.