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

[jfoj]

The one obvious difference between the 5.3l and 6.2l is they all have the same basic variable displacement oil pump, ALL but the newer L84 5.3l have a 2 stage oil pump that is controlled by a solenoid that is not serviceable, this is why there are different oil pump part numbers for the L84 5.3l, vs the L83 5.3l and the L86/L87 6.2l.

Please understand the variable displacement oil pump is the BASE for the 2 stage oil pump. The only difference on the 2 stage oil pump is the solenoid that boosts the oil pressure somehow. I beleive the default/failed/unplugged state of the 2 stage oil pump is high pressure.

I do not think there is enough known about the AFM/DFM behavior if the oil pressure is constanstly boosted. There would likely be a CEL/MIL/SES triggered as well.

Agree that there may be an oil starvation issue when all the DFM activity is happening.

#1 rod bearing is the absolute last bearing in the lubrication path, just behind the front crank bearing. Seeing probably more of these failures out of most bottem end failures, but there are also problems with the thrust bearing on the center main, have alse seen rod bearings #7 &#8 fail as well. Probably a number of different things going on here.

 

[viven44]

Unfortunately the 6.2l is a perfect storm for self destruction. Since the 10 speeds have showed up the problem has been even more prevalent due to the Low RPM/High Torque loading on the 6.2l.

10L80's final drive ratio (0.636) is honestly only slightly lower than even the 4L80s (0.696) and on our 2024, we are honestly never in the final drive gear ever. It takes too darn long to get there, so I've complained about poor fuel economy partly because of that. Can read here.

At a high level I share your sentiment on the poor engineering decisions by ALL manufacturers, not only GM, in the name of innovation. I work in a tech company and sadly when innovation is forced without a need, poor ideas do end up getting implemented often.

Very disappointing to see the 6.2L engine failures being reported everywhere (here, reddit) and we dodged a bullet buying wife's 2024 with the 5.3L. We strongly considered the 6.2L until we realized it needed premium fuel (yes that was the deciding factor!) ... I'm very skeptical even with the 5.3L DFM engine because I'm an old school carburetor/flat tappet guy and like to get into and out of my engine without the need for computers and technology and expensive replacement parts. Set of flat tappet cam and lifters is still affordable (But even that is under peril, more below).

Would be interesting to see what comes out of all this investigation. Premature to say what went wrong. Poor build, poor metallurgy ? Whatever it is, it is not a 6-sigma production. There is an eerie similarity to the flat tappet lifter/cam plague where the lifter and cam lobes flake off due to poor case hardening. Less prevalent but even the Ford 7.3L godzilla has some reportings of low-mileage roller cam/lifter failure due to flaking off.

All the suggestions on oil type, fuel dilution, oil temp can help ALL, but not the few that are sadly driving production outliers with the engines failing within 3000 miles???.. its a spectrum so the not so bad ones are still ticking timebombs... hopefully GM will do right by all and save themselves and everyone involved by getting to the root cause.