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

[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.