Fool me twice?

[R32driver]

Define "handful".... We have a family member that is a service adviser at a local GM dealership, and they have had up to 6 vehicles at a time in their "Bullpen" waiting on parts to fix this... Not everyone with the problem is on forums crabbing about it. He says there is a vehicle every week coming in with it.. PU trucks and Tahoe/Yukon's. And it isn't "Defined" to a certain build date. They've had them in on both sides of these dates, including 2022's. Also, you say the vast majority don't have this problem and I agree... but the key word is YET...

So we're somewhere between a handful and 10% (30-40 thousand vehicles in an average build year?) This issue seems to be luck of the draw at this point and I've concluded GM doesn't really know what the cause is and we can't in any way determine how widespread it is. If/when it happens to ours we'll have it fixed and move on with life. Wife loves this ride too much, it would have to spontaneously combust for her to consider getting rid of it

 

[Quark]

As with most failures of any type including this one they know what causes the problem but they don't have a fix that is good for GM.

 

[Toasty]

Really…. Define any 2021+ model year being pre-lifter issue? Have you not read up on how many of the K2XX ‘15-‘20 models have had lifter issues and lifter failures due to AFM? Hell there are even lifter issues in the 2007-2014 MY.

So GM changes the name to “DFM” instead of “AFM” and still each “fuel saving” system continues to have lifter issues and failures in the valve train.

I’ve had a Range DFM disable module installed on my ‘15 Yukon XL Denali for almost 80K miles now. Still had a failed lifter (covered under warranty, thank you GM dealership). Additionally, what I’ve learned is that at the end of the day AFM/DFM doesn’t even add that much more additional mpgs. We’re talking maybe an extra 5% +/- mpgs that the “fuel saving technology” systems might add. An increase in mpgs that is so negligible that I bet the majority of us would give up and forego if it meant we could go 100K+ miles without a top-end valve train failure, or worse catastrophic engine failure, at the expense of getting 5% less mpgs.


I agree with you 99%

The 1% being that american pushrod V8’s with all the added AFM/DFM mpg gas saving emissions pleasing ********* have not been being built for 100+ years.

Mfgs keep adding “technology” to save mpgs to please the emission requirements as much as they can so they can even keep producing ICE V8 engines. Meanwhile the very same “technology” is significantly reducing reliability of the age old simple pushrod V-8 design that you speak of.

Don't particularly care about your `15's issue, you're in the wrong thread, not to mention a different issue. My post, referred to the 2021 lifter issue that is related to the faulty spring in the lifter assembly, that was not in the earliest builds.

As for appeasing those that are making the CAFE rules that are causing this extra technology, you're preaching to the choir in here. Go vote. That's the only way to fix it. And I'll give you a hint, the current administration is not the right party to be voting for if you want that change.

 

[Hrocks]

Don't particularly care about your `15's issue, you're in the wrong thread, not to mention a different issue. My post, referred to the 2021 lifter issue that is related to the faulty spring in the lifter assembly, that was not in the earliest builds.

As for appeasing those that are making the CAFE rules that are causing this extra technology, you're preaching to the choir in here. Go vote. That's the only way to fix it. And I'll give you a hint, the current administration is not the right party to be voting for if you want that change.

Amen Brother.

 

[vcode]

Don't particularly care about your `15's issue, you're in the wrong thread, not to mention a different issue. My post, referred to the 2021 lifter issue that is related to the faulty spring in the lifter assembly, that was not in the earliest builds.

As for appeasing those that are making the CAFE rules that are causing this extra technology, you're preaching to the choir in here. Go vote. That's the only way to fix it. And I'll give you a hint, the current administration is not the right party to be voting for if you want that change.

Looks like the lifter issue may affect 2022's as well based on another post here.... :-(

 

[Zed Seventy One]

2021 Z71 5.3l purchased 12/20, 31k miles and no issues so far. Fingers crossed.