Main Bearing Failure with 6.2L at 3,200 miles

[WalleyeMikeIII]

That doesn’t make any sense. Why would it take a month to diagnose? Did you talk directly to GM about a rental, or did the dealer tell you that? As suggested, I think you need a different dealer- those guys are terrible.

As for fuel - I always use 91 (highest available in California.). Had a friend blow up an LS in a Corvette 10 years ago from using low octane gas and knocking, so I’m not messing around with that.

It makes me angry that you can't get 93 everywhere...unclear exactly why. Owners Mannual for 2021 recommended 93, in 2022 they changed it to say 91 (guessing this was marketing and/or legal requirement). Fortunately, where I live, we have a couple stations that have 93, and Costco has 92 for reasonable money. I always go with the 93, unless in a pinch, drop to 92.

Was just curious if those having engine issues were using 87 or something. Clearly there is some issue w/ the 6.2's. Hope GM figures it out, as I do love the engine.

 

[Dilligaf34]

Yes I did contact GM customer service and they basically said they will not authorize a rental until its diagnosed to see if it is a warranty issue. I have a friend that is a tech at another local dealer and according to him they have 6 vehicles waiting on 6.2 engines. He also told me he put a motor in one last week (spun all 8 rod bearings) and when it was in his stall warming up after about 15 minutes it locked up. Pulled the new motor back out and the #8 piston was install backwards. Here is a pic of the oil from my filter. As far as time, I don't mind waiting a little bit I'm hoping they correct this issue and I get a good motor instead of a ticking time bomb.

 

[tooleyondeck]

Sorry to hear you’re dealing with that. It’s a shame that GM doesn’t have the same level of QC on the truck 6.2s bc the LT1 community rarely reports issues like this, if ever. Camaros and Vettes are typically driven a lot harder than SUVs.

 

[KMeloney]

Along with the metal flakes in the oil, were there any other warning signs (at least in retrospect) that the engine was going to fail?

 

[Dilligaf34]

I thought I heard something like a spark knock or rattle and oil life was at 11% so I went ahead and changed the oil and ran it thru a paint strainer (full of very fine metal). Than about 10 miles later it rattled away and locked up.

 

[ChrisYukon]

I thought I heard something like a spark knock or rattle and oil life was at 11% so I went ahead and changed the oil and ran it thru a paint strainer (full of very fine metal). Than about 10 miles later it rattled away and locked up.

For future reference, changing the oil will never solve any problems that an engine is having.

 

[KMeloney]

For future reference, changing the oil will never solve any problems that an engine is having.

I believe that. But can it show you that there IS a problem?

 

[Marky Dissod]

For future reference, changing the oil will never solve any problems that an engine is having.

I believe that. But can it show you that there IS a problem?

Yes, but only IFF you send the used oil to a laboratory for analysis.
Still can't figure out why one can't send used oil filters for analysis ...

 

[KMeloney]

Yes, but only IFF you send the used oil to a laboratory for analysis.
Still can't figure out why one can't send used oil filters for analysis ...

The metallic flakes in the pic above aren't an indicator? Is that amount of flake "normal"?

 

[StephenPT]

Yes, but only IFF you send the used oil to a laboratory for analysis.
Still can't figure out why one can't send used oil filters for analysis ...

You don't need any oil analysis other than visual to identify spun bearings....

The GM TSB specifically tells the technician to take off the oil filter and look inside for metallic flakes. No oil analysis necessary.

 

[Marky Dissod]

The GM TSB specifically tells the technician to take off the oil filter and look inside for metallic flakes.
No oil analysis necessary.

So the GM tech is going to 'visually' inspect for metallic flakes?
How much you wanna bet they're going to assign techs with bad vision specifically in terms of examining for ultrafine metallic particles?

 

[StephenPT]

So the GM tech is going to 'visually' inspect for metallic flakes?
How much you wanna bet they're going to assign techs with bad vision specifically in terms of examining for ultrafine metallic particles?

We're talking about spun main bearings here. This isn't an issue a dealer can say "can't replicate the customer complaint." The engine is either locked up or sounds like it's about to be - visual inspection of the oil filter is all that's needed to open the warranty claim through GM and get a new crate motor ordered.

 

[Dilligaf34]

Talked to a friend that is a tech at a local dealership, sounds like this problem is getting worse. The parts that are needed to do the engine replacement are going on back order, motor, radiator, gaskets, o-rings.

 

[Geotrash]

Talked to a friend that is a tech at a local dealership, sounds like this problem is getting worse. The parts that are needed to do the engine replacement are going on back order, motor, radiator, gaskets, o-rings.

The interesting thing about these (to me, at least) is that many of them are making it to 30, 40, 50K before spinning a bearing. Normally, defective bottom end parts will trigger a mechanical failure in the first few thousand miles. In this case, GM likely has no way to know how many of these are doomed until their red-faced owners come storming through their doors.

 

[Marky Dissod]

The interesting thing about these (to me, at least) is that many of them are making it to 30, 40, 50K before spinning a bearing.
Normally, defective bottom end parts will trigger a mechanical failure in the first few thousand miles.

Well, obviously, these are also defective
(even if GM would love to increase the number of engines that fail at approx 180,000 miles).

My suspicion is faulty metallurgy.

 

[Geotrash]

Well, obviously, these are also defective
(even if GM would love to increase the number of engines that fail at approx 180,000 miles).

My suspicion is faulty metallurgy.

Yes, they're absolutely defective. I only meant that it makes it even more unnerving to not know if/when it's going to grenade. And I suspect you're right about the metallurgy.

 

[Marky Dissod]

Since accountability at GM is (at least initially) NOT an immediate priority, it'll be RELATIVELY easy for prospective customers to figure out which vehicles to avoid buying after a short while.
Reminded of a scene in
Fight Club
where 'Tyler Durden' explains his job as a 'recall coordinator', whose job it was to apply
The Formula (should we initiate a recall?):
"Take
the number of vehicles in the field - A
multiply by
the probable rate of failure - B
then multiply (A*B) by
the average out-of-court settlement - C
(A*B)*C = X
"If 'X' is less than the cost of a recall,
WE DON'T DO ONE." - Tyler Durden

 

[JasonGMC]

I also joined the forum as my 2023 GMC AT4 with 6.2 spun the bearings and the engine seized with 11,000 miles on March 11, we were about 110 miles from home. It was towed 20 miles to a larger GMC dealer. The dealer called the next day and notified me the seized engine due to a spun bearing. The engine, radiator, 400amp fuse block, oil cooler lines along with many other parts were replaced. The engine seized at 3:30 on a Monday and the dealer called Friday morning and said it was done and ready to be picked up. Every tank of fuel since new was 91 octane or better and the oil had been changed twice. I love the 6.2 10 speed platform. I traded my 2017 GMC Duramax for a 2019 Silverado with the 6.2 and traded again for a 2021 Silverado 6.2 and now this AT4 6.2. I put on 20k miles per year with 10k pulling my walleye boat and have never had a problem until now.

 

[KMeloney]

If there were to be a TSB with measures to avoid this situation, what would it look like? What would need to be replaced to avoid these seizures?

 

[WalleyeMikeIII]

If there were to be a TSB with measures to avoid this situation, what would it look like? What would need to be replaced to avoid these seizures?

I don't think the general public knows just yet...

There could be several causes, and we don't yet know that the cause is, for the rod bearings, could be:
Oil Pump
Bad Bearing metallurgy
Bad machining on crank shaft
Clogged Oil Passages
Bad Bearing Manufacturing tolerance
Bad Rod Manufacturing tolerance
Bad Crank Manufacturing tolerance
Foreign Material
Bad Oil
etc...

For Main Bearings, causes could be different yet, but seems like the bulk of fails we are reading about are rod bearings, not main bearings.

Here is an interesting article on rod bearing fails.

https://www.kingbearings.com/wp-content/uploads/2014/10/Engine-bearing-failures-and-how-to-avoid-them1.pdf