2nd time Lifter Failure... 2021 Yukon AT4

[Quark]

GM is leaving buyers hanging on this one. They are stuck with a bad design and possibly going under and their only consolation is that the competition is in the same boat. Buyer beware.

 

[Usdmskyline20]

I'm now convinced it was not a bad batch but just a design flaw. My Yukon was built in May; lifter failure at 5000 miles. Dealer replaced both banks, all 16 lifters. 500 miles later, lifter failure AGAIN. The 75k pile of sh*t is being towed to dealer again tomorrow. If you are on the fence about getting a 21, just go visit the service bay at your local GMC dealer. Mine had 7 Yukons/Tahoe's currently in for lifter failure. It's definitely not just a small vocal few having this issue.

Plenty of threads on this, but I wanted to let people know, just because you had both banks replaced with the supposed *fixed* batch of lifters, you aren't in the clear.
So frustrating, as this was the perfect vehicle for my family. Now I'm trying to find a Jeep Dealer with an allocation for a Wagoneer.

Did yours come equipped with Afm?

 

[Xsbank]

Covid cars. I just took a beating getting out of a 2021 Ford Exploder ST that was a nightmare and no parts for months. Total POS. I traded it on a 2020 Denali demo and what a concept, everything works! For continued happiness, buy a BC (before Covid) car, when everything was “normal” in our factories.

 

[Fireman591]

It is a design flaw that has doubled with the DFM system. This guy explains it well and our dealers up here are seeing wear marks near the base of the push rods so harmonics might be a big chunk of this puzzle.

 

[mikeyss]

Covid cars. I just took a beating getting out of a 2021 Ford Exploder ST that was a nightmare and no parts for months. Total POS. I traded it on a 2020 Denali demo and what a concept, everything works! For continued happiness, buy a BC (before Covid) car, when everything was “normal” in our factories.

I'm curious, what all was wrong with your Explorer ST?

 

[Hrocks]

I follow a good number of mechanics on tiktok. Most of them are very reputable and work for reputable deals. For GM, The 20's and 21's are the worst years for lifter failures and DOD issues. Toyota 4Runners - avoid. They are dropping cranks between 5k & 10kon the 20's and 21s. FCA (dodge/fiat/jeep/etc) have spare transmissions cause the 8 speeds are going to explode...and they are 3-6 months backordered, worse than the GM lifters and 6L80 transmission parts. Ford has electrical and module problems out the wazu. Honda's, Nissan, and a couple others all have module issues.

It doesn't matter the brand you buy. Anything in the 20-21 years is in for issues. And they expect a crap ton more because the cars that have been sitting waiting for the modules with the chip backorder issue, are going to have other issues because the cars have been sitting for a year or more without running

I would take exception with the "Anything in the 20-21 years is in for issues". (except for all GM 5.3 and 6.2 motors ) GM is notorious for developing new platforms on the backs of their early adopter customers, which the past couple of full sized SUV's, has lasted for at least the first TWO years. It's very unfortunate and totally avoidable with adequate engineering development. I had enough of being a guinea pig when I had an '07 Escalade...I lived at the dealer. Cadillac was NO help. In any case, I have moved on and own two BOF Lexus SUV's and my great 2010 Tahoe LTZ. IMO, the last and best full size SUV platform was the 2013 of the GMT 900. It took GM until the last two years of the GMT K2XX to get them right. They have apparently taken the same approach on GMT T1XX...unexcuseble

 

[jayoco]

I'm now convinced it was not a bad batch but just a design flaw. My Yukon was built in May; lifter failure at 5000 miles. Dealer replaced both banks, all 16 lifters. 500 miles later, lifter failure AGAIN. The 75k pile of sh*t is being towed to dealer again tomorrow. If you are on the fence about getting a 21, just go visit the service bay at your local GMC dealer. Mine had 7 Yukons/Tahoe's currently in for lifter failure. It's definitely not just a small vocal few having this issue.

Plenty of threads on this, but I wanted to let people know, just because you had both banks replaced with the supposed *fixed* batch of lifters, you aren't in the clear.
So frustrating, as this was the perfect vehicle for my family. Now I'm trying to find a Jeep Dealer with an allocation for a Wagoneer.

Fill out your information: https://www.classaction.org/gm-lifter-problems-lawsuit

 

[RobFog]

Oh man that’s terrible to hear. Your build date is 2020 or 21? Seems like high mileage in less than 2 months for a 21 and already on the 2nd failure good lord…

I believe he said 75k$

 

[RobFog]

I believe he said 75k$

We had 2 lifters go out in July at 3k miles. They replaced all 16. Now 6 months later we are having the same issue.

 

[wsteele]

It is a design flaw that has doubled with the DFM system. This guy explains it well and our dealers up here are seeing wear marks near the base of the push rods so harmonics might be a big chunk of this puzzle.

The pushrods bending has nothing to do with harmonics or design flaws. The push rods can be bent because of the failure mode of these particular lifters (some of the time). Historically, when an AFM lifter fails, it fails to lock back into normal lifter mode. The top half of the lifter moves up and down as the cam lobe on that valve moves up and down as it rotates. This mode allows the pushrod to stay in the cups of the lifter and rocker.

In the 2021 MY lifter failures, the failure mode of the lifter is the lock pin spring breaks and the upper half of the lifter can jam in the down position. In this failure mode, the upper half stops moving up and down in time with the cam lobe and hence, when the cam lobe moves off the "valve actuated" position, the upward pressure on the push rod that keeps it in position of the cups of the lifter and rocker that it normally rides in is removed and the pushrod can fall out of the cup in the rocker and potentially also the lifter. With the next revolution of the engine, the cam lobe comes around and pushes the lifter up, the push rod can be misaligned outside the two cups and jammed against an immovable object (or at least a portion of the rocker arm with less movability) and immediately bent.

When the DFM lifter fails and the failure mode is the lifter just keeps going up and down in cylinder deactivation mode (never locking back into normal fire mode, but not jammed down), even when the engine is commanded to be in V8 mode, you get the hard miss, the CEL, the Christmas tree of misleading lights and messages, a failed lifter, but no bent pushrod.