My brand new, 2021 GMC AT4 was diagnosed with a "bent" lifter.
The other day, I was rolling down the highway at about 50-60mph when I started hearing a clanking/knocking noise followed by some vibration. I took it easy getting it home as I had no idea what was causing it. I didn't drive it again until I took it in to the dealer. When I started it up, it began making the noise and vibrating again, even while idle in park.
They told my it was a "bent" lifter. Only have 9.5k miles on my truck. They are ordering me new parts, but I'm worried they're just gonna throw the same new factory lifters on there and I'll run into this same issue again.
Has anyone else had this issue? More importantly, has it led to any other components in the engine and/or transmission to fail?
This is not an uncommon issue for GM. It can be anything from a simple lifter replacement to replacing the motor. AFM lifters have been a problem since their introduction in 2005 or so. Newer motors are better than the first generations. There are dozens of threads about this on this site.
You can thank the EPA and Congress for forcing them to try to get the very last .01 mpg out of these motors. It's a flawed design from the get-go but it's what GM came up with to try to meet the CAFE standards. They cannot put alternate parts in the motor under warranty. GM and the government would never allow it.
You can put in aftermarket, non-AFM parts but that would void your GM warranty, even though it would become more reliable. Catch-22.
Let the dealer fix it. It might not ever happen again. If it does, you might get a brand new motor out of it.
Okay thanks for the advice GBSierra. I would imagine it would do the exact same thing if they are gonna throw on the exact same parts. But I'll cross my fingers and hope for the best before throwing on the AFM delete and losing my warranty.
Not all AFM motors fail, some fail early (<50K), some fail very late (200K+). Hit-and-miss, that's what it is. Like Gary said, let the dealer fix it and use your warranty accordingly. If it fails again, you might be in for another motor.
No, these things shouldn't happen, but unfortunately the regulations have put us where we are at and we just have to live with it. Grass is not necessarily much greener on the other side, either.
There is a known issue with the 2021 5.3 and 6.2 motors for bending lifters before 10k and there is not currently a fix for it other than replacing them with the same ones. Seems to be happening more with the 6.2 than the 5.3.
On my '14 6.2 It dropped a valve and they replaced the heads. So I would assume instead of replacing a lifter and rebuilding the heads they would just replace them.
My brand new, 2021 GMC AT4 was diagnosed with a "bent" lifter. The other day, I was rolling down the highway at about 50-60mph when I started hearing a clanking/knocking noise followed by some vibration. I took it easy getting it home as I had no idea what was causing it. I didn't drive it again until I took it in to the dealer. When I started it up, it began making the noise and vibrating again, even while idle in park. They told my it was a "bent" lifter. Only have 9.5k miles on my truck. They are ordering me new parts, but I'm worried they're just gonna throw the same new factory lifters on there and I'll run into this same issue again. Has anyone else had this issue? More importantly, has it led to any other components in the engine and/or transmission to fail? Thanks.
I also have a 2021 Serra Denali that had only one bank of lifters and pushrods replaced. They (GMC) will not authorize the replacement of the other bank's part because they are not currently failing. I sent an email to Mary Barra, Chief Executive Officer of General Motors, informing her that I am an older woman who drives the truck. Also, we are planning on a vacation this September 2023 with my daughter, young grandson and pets from Georgia to Alabama. I am most concerned that the other bank will fail during our trip. Ms. Barra forwarded my email to an Executive Advisor who did nothing but state the policy regarding the replacement of the parts. She told me I could have the parts replaced, but at my own expense. No way! GMC installed defective parts in my truck and now they will not stand behind them. This was my third and last GMC product ever to be purchased for my family. My safety, my daughter, my grandson, and my pet's safety is obviously not a concern for them. I just pray to the good Lord that we do not get stranded in an isolate area.
The lifter failure deal is terrible.
Ive got a SM at a local dealership that will call me up at times to come in and disable the AFM/DOD junk in the tune.
They replaced the lifters in a '19 Tahoe 7 times in 12,000 miles. Bad part is this was a county judge's tahoe and they got tired of dealing with it. Made some quick easy money and they havent had a issue with it yet and that was 2 years ago.
I cringe when one my buddys buys a newer GM truck.
My 14 6.2 had a broken valve spring at 68k. GM replaced both heads after it sat in the dealerships shop for almost 1.5 months. I never had another issue with that after. Now the transmixer was a different story.
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