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2021 GMC Sierra 3.0 issues

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26K views 5 replies 5 participants last post by  Ibundyg  
#1 ·
New to this forum, and sorry to vent, but stumbled on this and curious if any other owners are having these issues on the 3.0 Duramax. I bought the truck new Dec 2020.

At about 3500 miles, I kept noticing a smoking plume from the engine right side. Took to dealer, determined that there was a flaw in the casting of the turbo. Oil was dripping intermittently on the exhaust manifold. GM replaced the turbo under warranty. 10 days on the hoist waiting for parts.

At about 18,000 miles I got a "reduced engine power" error, check engine light. Would not start, towed to dealer. Result was a faulty bracket that connects the ground wire from the catalytic converter to the engine. They do not make this bracket separate. Dealer had to replace the entire catalytic converter on the truck to repair under warranty. 14 days in shop.

Last week same thing happened. Was able to drive it to the dealer before it would not restart. Determined same bracket broken again. Need to replace as before! GM sending someone to look at it before replacing. Insane they don't make a $10 part. Have to replace entire converter for solution.

Turbo was a $6000 plus warranty claim, converter over $9000 warranty claim, and sure it will be the same second time. $25,000 in warranty repairs on a $60k truck in under 25,000 miles??

Anyone out there have any same issues? They claim I'm alone with these problems. All told, the new truck has sat on the dealers hoist for over a month since new in Dec. Frustrating for sure...not sure what else to do at this point. When the truck runs, it's an awesome experience with no complaints! Lol. Hope someone out there can shed light on anything they may know or heard. Thx!
 
#2 ·
Have not seen those specific issues in any of the forums regarding the lm2. Most common are the rear main seal and the continuous starting /no start issue that seems to be plaguing a large portion of the 21 trucks.
 
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#4 ·
New to this forum, and sorry to vent, but stumbled on this and curious if any other owners are having these issues on the 3.0 Duramax. I bought the truck new Dec 2020.

At about 3500 miles, I kept noticing a smoking plume from the engine right side. Took to dealer, determined that there was a flaw in the casting of the turbo. Oil was dripping intermittently on the exhaust manifold. GM replaced the turbo under warranty. 10 days on the hoist waiting for parts.

At about 18,000 miles I got a "reduced engine power" error, check engine light. Would not start, towed to dealer. Result was a faulty bracket that connects the ground wire from the catalytic converter to the engine. They do not make this bracket separate. Dealer had to replace the entire catalytic converter on the truck to repair under warranty. 14 days in shop.

Last week same thing happened. Was able to drive it to the dealer before it would not restart. Determined same bracket broken again. Need to replace as before! GM sending someone to look at it before replacing. Insane they don't make a $10 part. Have to replace entire converter for solution.

Turbo was a $6000 plus warranty claim, converter over $9000 warranty claim, and sure it will be the same second time. $25,000 in warranty repairs on a $60k truck in under 25,000 miles??

Anyone out there have any same issues? They claim I'm alone with these problems. All told, the new truck has sat on the dealers hoist for over a month since new in Dec. Frustrating for sure...not sure what else to do at this point. When the truck runs, it's an awesome experience with no complaints! Lol. Hope someone out there can shed light on anything they may know or heard. Thx!
Sierra Denali ultimate 3.0. Left me stranded on the highway. Terrible noise coming from the turbo and reduced power, tons of smoke billowing from behind. Towed to the dealer and somehow oil got into the turbo. Ruined the turbo and emissions system. No idea how that could happen with 7k miles on the truck.