2022 Z71 Suburban 6.2L bent lifters

[21TahoeDisappoint]

With regard to the "bad parts" vs. "bad design" issue, if it is simply bad parts, why hasn't GM issued a recall? They know what batches of parts, or mfg. dates of vehicles were subject to poor quality (due to covid?). I was also under the impression (perhaps incorrectly), that there is a new AFM in the 2021/2022's?

All I know is that I've had many vehicles over the years, and NONE have had the major engine failure that my Tahoe had at 7,000 miles. Sure, when it happens to you it really hits home, but is should not happen with a new $80k vehicle at 7,000 miles, let alone, 5,000 or 500 OR after repair with "correct spec" parts. That, in my view, is either bad design or stupidity to keep using faulty parts. GM has handled this in dismal fashion, most likely to prevent wider awareness of the issue.

 

[Quark]

Exactly, why not recall the bad springs and prevent further erosion of their reputation. This bad spring lot BS was fed to us by internet ninjas and perpetuated by fanbois.

 

[drmoose]

IMO, they did not issue ay recall with the bad lifters primarily because they didn't have the parts to support a recall. On my first trip to the dealer for the lifters, it was a 3 week wait, and that was in a situation where I was pushed ahead of others in line since my vehicle had already spent 28 days in for service a few months prior for something else. The second lifter replacement was faster, but still took a week+.

You can't issue recall if you don't have parts to fix the recalled vehicles. While it is clearly a safety issue, OTOH it is still a roll of the dice whether one is going to go bad. So my guess is GM said lets roll the dice and stretch out the fixes.

 

[21TahoeDisappoint]

Lack of recall likely not due to lack of availability of parts (they are apparently getting parts to repair anyway). And if there was a recall, GM would get with suppliers to expedite production of parts with correct spec to conduct the recall. In fact, they would announce the recall, and then let you know when the dealer has the parts to fix. I've had this on other recalls on other vehicles (for things not as serious). The NTSB may require a recall (as engine failure on highway a safety issue), and the GM legal department would likely support a recall announcement as a positive fact pattern to defend against the inevitable class action suits that GM has become quite adept at stalling and keeping quiet. My guess - the GM engineering department is working overtime to try to come up with a fix. No success yet.

Cylinder deactivation is a failed technology, and almost without a doubt the root cause of this. NOT a batch of bad parts and not isolated to specific build dates with "in-spec" parts, but covid weary employees on the production line.

Would like to know - of other manufacturers utilizing cylinder deactivation - how many have the same problem with lifters?

 

[Fless]

You can't issue recall if you don't have parts to fix the recalled vehicles. While it is clearly a safety issue, OTOH it is still a roll of the dice whether one is going to go bad. So my guess is GM said lets roll the dice and stretch out the fixes.

Certainly they can and do issue the recalls without parts availability. Think of all of the airbag recalls and how long it's taking to get replacements; the recalls were issued long ago. My Fusion has one of those that's over a year old now.

 

[SAdude]

I'm in the camp of this was a bad batch of parts. If it's a DFM design issue then we should be hearing from more owners outside of the timeframe of bad parts specified by GM. From those who post build dates I have seen very few failures after March 2021 and I have only read about one or two '22 owners and even these might be explained by bad parts still circulating. I would be interested if others are hearing otherwise. Also why would GM issue a bulletin requiring dealers to replace all lifters of any engines in unsold vehicles manufactured in that timeframe? That would be a waste of time if they knew this was a design issue. I don't doubt that DFM could expose the bad parts and contribute to the failures, but there doesn't seem to be enough evidence that DFM is the root cause.

 

[wsteele]

I'm in the camp of this was a bad batch of parts. If it's a DFM design issue then we should be hearing from more owners outside of the timeframe of bad parts specified by GM. From those who post build dates I have seen very few failures after March 2021 and I have only read about one or two '22 owners and even these might be explained by bad parts still circulating. I would be interested if others are hearing otherwise. Also why would GM issue a bulletin requiring dealers to replace all lifters of any engines in unsold vehicles manufactured in that timeframe? That would be a waste of time if they knew this was a design issue. I don't doubt that DFM could expose the bad parts and contribute to the failures, but there doesn't seem to be enough evidence that DFM is the root cause.

On another board a guy who works at the Tonawonga Engine assembly plant (and also owns a 2021 Silverado with a DFM engine) was the first guy I saw who posted about the bad batch of lifters and the cut-off date. He went on to post how to tell if the engine was built in the window of where the bad lifters were possibly being used (there is a sticker on the back of the cylinder head that has the plant code, the shift the engine was built on, the Julian date of the build and a sequence code). He explained it was a batch of pin lock springs that got improper heat treating that were used in the bad lifters. Apparently the improper heat treating causes them to break early in their life, which results in the lifter staying in DFM active mode even when the DFM oil pressure is removed. Apparently pieces of the spring can jam the lifter in a partially collapsed mode such that the pushrod falls out of its socket in the rocker arm (no upward pressure from the lifter spring keeping the pushrod in place), subsequently bending the push rod the next time the cam lobe comes around if the push rod happens to be resting in a place that inhibits its upward motion (like against the rocker trunion).

Unlike many who post on public forums, he certainly was credible. Everything he said about the dates and failure mode has jived with the feedback I have gotten from my dealer on what they have seen in these late 2020, early 2021 trucks.

On the reliability of AFM and DFM lifters (in general), my 5.3L 2007 Yukon, I bought new, has AFM. For its first 60K miles that truck pulled a 5K lb enclosed trailer to almost every road course West of the Rockies (and a few East of the Rockies). It now is well into six figures on the odometer and has never had a lifter issue.

A quick back of the envelope calculation of how many engines GM has built with AFM and DFM lifters (the same lifter design all along) is in the many 10's of millions. Anyone who thinks the issue is a design problem just doesn't know what they are talking about.

 

[SlimIm17]

I don't understand the perspective that this lifter issue is due to a bad batch of parts. If so, GM would have/should have announced a recall, as they would know what vehicles had the "bad" parts. The fact that this issue continues, and now is seen in 2022 models, is evidence (in my view), that this is a design flaw and not associated with out of spec parts. Furthermore, the failure mode is fairly high (based upon my conversations with my service advisor). So this isn't something that I thought "oh this happens, but it will be fixed and I'll go on down the road with my new $80k vehicle". I dumped it immediately, and glad I did as we see subsequent failure on vehicles with both banks repaired.

I'm done with GM forever. Not only is the approach of letting the general public vet new technology and design (at the publics' cost and inconvenience) irrational, but the absolute absence of honest communication and proposal of a cogent resolution is unforgivable. Doesn't GM understand the value of brand and reputational damage?

Is there any hard data on how many L84's have lifter failure? Have a '21 Z71 with 13,000 miles, that was built Jan 2021. No issues so far (and love the vehicle). Have anxiety reading all these threads about lifter failures. What's the real failure rate? Like 1 in 10, 1 in 100?

 

[TrueAt1stLight]

I was “1 of 1” with my 21’ Denali at 12,995 miles. I could never trust it again and sold it, then funded a 22’ identically-optioned last week. Crazy thing is the 21’ sold for $1,045 over MSRP with nearly 20k miles. Clown world.

 

[SlimIm17]

I was “1 of 1” with my 21’ Denali at 12,995 miles. I could never trust it again and sold it, then funded a 22’ identically-optioned last week. Crazy thing is the 21’ sold for $1,045 over MSRP with nearly 20k miles. Clown world.

Wow. You are a glutton for punishment! Curious - did you sell the '21 back to the dealership as a trade in?