Lost the 6.2 (was: May have Lost the 6.2)

[WalleyeMikeIII]

Headed out after work tonight, was going to head to Costco after work. Started up the Denali, drove about 2 miles, started hearing a loud knock/rattle from the engine. Sound reminded me of a playing card in the bicycle spokes. Pulled over, put it in park, could clearly hear the knocking, it varied with engine RPM. My GMC dealer was about 3 miles away, so I gingerly drove it to them, pulled in the service drive. Service manager popped the hood and listened. He said, "Definitely coming from the engine. This is a 6.2, right?"

I answered, 'Yes, of course."

He said, "doesn't sound good. I don't want to send you out of here with it."

My service advisor wrote it up, said they don't have a loaner right now, but offered the shuttle to take me home. He said after diagnosing tomorrow, he will call. If it is the engine, they will get me a looaner or a rental.

Details:
Odometer at 44,780
Recall was performed and passed pico test in June at 38k, been on 0W-40 since then.
Had a paid oil change at 43,200 about 2 weeks ago, along with front and rear diff fluid change, transmission fluid and filter, transfer case fluid, and replaced the battery.

Engine still ran when I left the dealer at 5:30, but is knocking badly. Guessing I'm in for a new engine, but we will see tomorrow; I'll keep you all posted.

 

[GMCnewbee]

Wow, talk about worst case. I also have a 2022 Denali, but only at 25k miles. Mine did pass the PICO test recently. Now more to worry about. Sorry that it happened to you, but much thanks for the report.

 

[Joseph Garcia]

Really sorry to read this.

 

[Vladimir2306]

Judging by the sound, it's likely the connecting rod bearing has become tangled with the crankshaft. Exactly what I said happened. The Pico test is just a smokescreen, just like the 0-40 oil. The good news is, your engine didn't seize up, so it won't need replacing, but repairing it. It's not difficult: replace the bearings, crankshaft, oil cooler, and lines, oil pump.

 

[Antonm]

Details:
Odometer at 44,780
Recall was performed and passed pico test in June at 38k, been on 0W-40 since then.
Had a paid oil change at 43,200 about 2 weeks ago, along with front and rear diff fluid change, transmission fluid and filter, transfer case fluid, and replaced the battery.

Is it safe to assume that it was running 0W20 up until the test 38K miles?

If so the bearings might have already been damaged during those initial 38K miles, but the PICO test should have detected that. Please keep us updated with what's going on as the saga unfolds.
...

 

[WalleyeMikeIII]

Is it safe to assume that it was running 0W20 up until the test 38K miles?

If so the bearings might have already been damaged during those initial 38K miles, but the PICO test should have detected that. Please keep us updated with what's going on as the saga unfolds.
...

Yes, all service performed at GMC dealer, oil was 0W-20 GM Dexos w/ OEM Filters until the recall performed in June.
Oil change interval was always 4000-5000 miles, except the first one was at 3k.

Dealer called about an hour ago said mine was next up for diagnosis. Will let you all know when I hear the answer.

 

[Antonm]

Judging by the sound, it's likely the connecting rod bearing has become tangled with the crankshaft. Exactly what I said happened. The Pico test is just a smokescreen, just like the 0-40 oil. The good news is, your engine didn't seize up, so it won't need replacing, but repairing it. It's not difficult: replace the bearings, crankshaft, oil cooler, and lines, oil pump.

If the main bearing shells spun (which is typical) then the block is trashed too. Dealers here charge such a high labor rate, that its cheaper to replace an entire engine, than it is pay the labor needed to repair it.

As for the 0W40 oil, no it will not fix bad machining or remove debris that was left in an engine, but it does provide an increased safety margin with literally no downsides or adverse affects (other that perhaps it cost slightly more) .There is no use case, no scenario, no environmental condition ( not a single one), where 0W20 does a better job than 0W40 at protecting the engines rotating components. The only advantage 0W20 has is it offers a slight increase in fuel economy.
...

 

[WalleyeMikeIII]

Dealer just called. Rod bearing debris in oil pan. New engine, radiator, oil cooler, lines, etc.

GM is renting me a full size GM suv until repairs are done.

Expecting it to take 30-45 days.

 

[LEsoftballdad]

That really stinks. Will you keep the vehicle after they install the new engine?

 

[B-train]

That really stinks. Will you keep the vehicle after they install the new engine?

If I were him, I'd keep it around since all major engine components are new including the radiator. And, it should come with a decent warranty.

@WalleyeMikeIII - I'd inquire what the replacement components come with for a warranty. I think if GM pays the bill, you get 2 yr/24k (engines may be different?). If it's customer pay, then its the 3 yr/100k from what I've been told in the past. This situation could be entirely different due to GM getting slapped on the pee-pee.

 

[WalleyeMikeIII]

That really stinks. Will you keep the vehicle after they install the new engine?

Haven't made any decisions yet. In theory, it is as good or better than it was after it is repaired. I've got plenty of time to decide that.

Getting a similarly equipped new XL Denali will cost me $40-50k. That would make the cost of driving this one more than $1/mile...kind of steep.
Worse yet, one of the advantages of my Just past CoVID era Yukon is I have all the stuff in the Denali Reserve package except the RSE, which I don't want or need anyway.

Impossible to buy one similarly equipped now that doesn't have the RSE...

 

[WalleyeMikeIII]

If I were him, I'd keep it around since all major engine components are new including the radiator. And, it should come with a decent warranty.

@WalleyeMikeIII - I'd inquire what the replacement components come with for a warranty. I think if GM pays the bill, you get 2 yr/24k (engines may be different?). If it's customer pay, then its the 3 yr/100k from what I've been told in the past. This situation could be entirely different due to GM getting slapped on the pee-pee.

I need to ask that. That said, rignt now my vehicle says I have a 15yr/150k mile Engine Warranty for crankshaft and rod bearings...not sure how the engine replace affects that...since mine originally passed the Recall test and got given that warranty.

 

[Fless]

FWIW GM Authority says all vehicles affected by the recall get the extended warranty, whether engine passed PICO test or was replaced:

https://gmauthority.com/blog/2025/06/gm-6-2l-v8-l87-recall-replaced-engines-benefit-from-extended-warranty-coverage/

 

[Joseph Garcia]

I am SO sorry to read this. You've been an outstanding member of this Forum, and it hurts me to read about a Member's misfortunes with GM's manufacturing policies and processes. It really sucks, particularly with the amount of investment required to purchase one of these trucks.

You deserver better!

 

[Bigburb3500]

Maybe I’m missing something… I know the convenience factor sucks majorly but don’t we WANT our members to be affected and GM to not give any runaround on replacing [arguably] the most important part of the truck? Lol

I’m over here thinking: Dang I would love my engine to implode, not hurt my family, me or anyone else AND GM no-questions replace my engine AND give me an extended warranty. Lol. I think it speaks volumes that a member of the forum had this issue and seems to have it resolved in less than 72hr.

 

[Marky Dissod]

Maybe I’m missing something… I know the convenience factor sucks majorly but
don’t we WANT our members to be affected and GM to not give any runaround on replacing [arguably] the most important part of the truck?

I’m over here thinking: Dang I would love my engine to implode, not hurt my family, me or anyone else AND GM no-questions replace my engine AND give me an extended warranty. I think it speaks volumes that a member of the forum had this issue and seems to have it resolved in less than 72hr.

What you actually want, is for GM (Mary Barra?) to not pinch pennies, properly finish & clean the crank & rod bearings, and get it right the first damn time -
not give rise to L87 support groups (12 people have been injured), not have articles like this become a thing

https://gmauthority.com/blog/2025/12/multiple-gm-l87-engine-lawsuits-consolidated-into-one/

and not make people wonder if their L87 will be next.
Sure, once they screw up, they need to own up to their mistakes, but the mistake is something GM needs to never do again in our lifetimes.

I'd rather buy another GMT800 or GMT900 ...

 

[WalleyeMikeIII]

Maybe I’m missing something… I know the convenience factor sucks majorly but don’t we WANT our members to be affected and GM to not give any runaround on replacing [arguably] the most important part of the truck? Lol

I’m over here thinking: Dang I would love my engine to implode, not hurt my family, me or anyone else AND GM no-questions replace my engine AND give me an extended warranty. Lol. I think it speaks volumes that a member of the forum had this issue and seems to have it resolved in less than 72hr.

Well, given the actual manufacturing situation, yes, getting a new and hopefully non-defective engine is probably the best thing. But I tend to agree with the previous poster, I’d like to just have a nice reliable GM small block V8 like I had in my 2004 and 2013 Suburbans where I never had to worry when I hit start whether I make it to my destination or not.

It’s not like GM doesn’t know how to do this. They did it solid for like 25 years or more.

 

[WalleyeMikeIII]

I am SO sorry to read this. You've been an outstanding member of this Forum, and it hurts me to read about a Member's misfortunes with GM's manufacturing policies and processes. It really sucks, particularly with the amount of investment required to purchase one of these trucks.

You deserver better!

Thanks @Joseph Garcia, appreciate the kind words. It’ll all get worked out, my dealer is being as good to me as he can, we’re really at the mercy of GM and whenever they can provide an engine. We’ll get through it. Nobody got hurt. Everybody made it home that’s what really matters

 

[Bigburb3500]

Well, given the actual manufacturing situation, yes, getting a new and hopefully non-defective engine is probably the best thing. But I tend to agree with the previous poster, I’d like to just have a nice reliable GM small block V8 like I had in my 2004 and 2013 Suburbans where I never had to worry when I hit start whether I make it to my destination or not.

It’s not like GM doesn’t know how to do this. They did it solid for like 25 years or more.

Now I fully agree with you and @Marky Dissod about this should not have happened in the first place. The error was “too simple” and it’s not like these are new engines.

I am 100% glad no one got hurt in your instance and I’m glad they are getting you taken care of in a timely fashion.

As much as I’m fan of new tech I think it’s deteriorating quality in many vehicles.

 

[blanchard7684]

@WalleyeMikeIII

Sucks to hear. I feel for the 6.2 folks.

At least you get a new engine