Potential Lifter Issue Post Factory “Fix”

[Seamus]

You have to read the article. Its not every single one that's affected. If it were you could argue a design problem. But these engines have been made longer then just 2021 and are still being made.

It's the supplied lifters that have a spring problem. A certain batch.

Oh I read it.

Number of affected vehicles: it’s currently not clear how many vehicles were delivered to dealers in need of a valve lifter repair.


this service update is for dealerships only and only affects vehicles that are en route to or have already been delivered to GM dealerships.

This is lawyer speak. I have owned several LT motors since 2014....this lifter issue has been on forums since then. But then there were only 4 collapsable lifters now it more, thus increasing the odds of it happening. So maybe a bad batch, but I doubt it, its just more of them in play and the rest is math increasing the percentage. The evidence is clear, they added more collapsable lifter to each engine and now there are more engines with lifter issues. If you really wanted to argue GM has had cheap lifter issues since 1997 with the new LS motor. They were maintenance sensitive but its always been an issue. When DOD came out.....everyone who has owned one for long lengths of time will get a bad lifter. Mind you there are only 4 of them in that motor.

This lifter issue is nothing new just more of them. When its happening in the first year and has continued for 3 years...houston we have a problem. Its all over youtube and all over every forum. Its an issue.

 

[DuraYuk]

Oh I read it.

Number of affected vehicles: it’s currently not clear how many vehicles were delivered to dealers in need of a valve lifter repair.


this service update is for dealerships only and only affects vehicles that are en route to or have already been delivered to GM dealerships.

This is lawyer speak. I have owned several LT motors since 2014....this lifter issue has been on forums since then. But then there were only 4 collapsable lifters now it more, thus increasing the odds of it happening. So maybe a bad batch, but I doubt it, its just more of them in play and the rest is math increasing the percentage. The evidence is clear, they added more collapsable lifter to each engine and now there are more engines with lifter issues. If you really wanted to argue GM has had cheap lifter issues since 1997 with the new LS motor. They were maintenance sensitive but its always been an issue. When DOD came out.....everyone who has owned one for long lengths of time will get a bad lifter. Mind you there are only 4 of them in that motor.

This lifter issue is nothing new just more of them. When its happening in the first year and has continued for 3 years...houston we have a problem. Its all over youtube and all over every forum. Its an issue.

In that case water pumps and transmissions are also design issues by your logic. As is the valve cover gasket and engine seals. Because they all can fail under warranty. Maybe even the brakes too.

Lmao.

 

[Geotrash]

My understanding is that while the collapsible lifters in the newer DFM engines (contain 16 of them) are the same design as previous AFM engines (contain 8 of them), they operate much more frequently in the DFM engines, significantly increasing the chances of failure. The lifters occasionally fail on the AFM engines but the root cause is often a poorly functioning VLOM (holds the oil flow control solenoids for the collapsible lifters). The design of the complete system that controls the lifters is different in the DFM engines as well. It’s also possible that there were slight changes to things like valve train geometry as some have alluded to elsewhere, but I’m not certain of that.

All of this to say that the design did indeed change when GM switched from AFM to DFM, with implications that increase the possibility (probability?) of failure of the system. Accordingly, people with these engines (DFM came to the trucks first in 2018 or 19, I believe, started having problems with them immediately. Yes, GM had a bad batch of lifters that increased the probability of failure significantly for those engines equipped with them, but the DFM system and the related component changes from earlier designs are also likely at issue here.

 

[DuraYuk]

My understanding is that while the collapsible lifters in the newer DFM engines (contain 16 of them) are the same design as previous AFM engines (contain 8 of them), they operate much more frequently in the DFM engines, significantly increasing the chances of failure. The lifters occasionally fail on the AFM engines but the root cause is often a poorly functioning VLOM (holds the oil flow control solenoids for the collapsible lifters). The design of the complete system that controls the lifters is different in the DFM engines as well. It’s also possible that there were slight changes to things like valve train geometry as some have alluded to elsewhere, but I’m not certain of that.

All of this to say that the design did indeed change when GM switched from AFM to DFM, with implications that increase the possibility (probability?) of failure of the system. Accordingly, people with these engines (DFM came to the trucks first in 2018 or 19, I believe, started having problems with them immediately. Yes, GM had a bad batch of lifters that increased the probability of failure significantly for those engines equipped with them, but the DFM system and the related component changes from earlier designs are also likely at issue here.

The probability of failure is still incredibly low. Water pump has a higher chance of leaking then you having lifter problems. Transmission has a higher chance of failing then lifters. I worked as a gm tech for years at a large volume store and didn't see hardly any. Now acadias and it's siblings ? There you have design issues especially in the transmission wave plate.

Still it sucks breaking down so I can understand people's frustrations.

 

[Geotrash]

The probability of failure is still incredibly low. Water pump has a higher chance of leaking then you having lifter problems. Transmission has a higher chance of failing then lifters. I worked as a gm tech for years at a large volume store and didn't see hardly any. Now acadias and it's siblings ? There you have design issues especially in the transmission wave plate.

Still it sucks breaking down so I can understand people's frustrations.

Your experience as a tech gives you a helpful perspective on how GM and service departments handle failures in the fleet, and if your experience was in the last 15 years, then you likely understand the AFM system and its relatively low failure rate. So thank you for that and I find it reassuring that you don’t think there is a more serious systemic or design problem with the DFM engines.

All of that said, I have done enough reading and review of available information here and elsewhere to still hold the opinion that there is an underlying design and/or manufacturing problem with the DFM system beyond a faulty batch of lifters. Enough that I would not buy a current generation of this vehicle with a V8 until the problem is better understood and more permanent resolutions are available from GM or elsewhere. Nothing you’ve said so far is enough to change that opinion. I would want to see a more complete engineering analysis from GM or a reliable 3rd party, which we probably won’t have for some time.

While admittedly not a scientific approach to analysis, if your comparison to other potential failures were logical, I would still expect to see at least a few people here with water pump or transmission failures, but we’re not seeing that. Some transmission shifting problems, sure, but not failures. I truly don’t mean to be argumentative at all. Just trying to lay out my logic for thinking about it as a design problem.

 

[tom3]

When we first got our 2019 (5.3L) I didn't know anything about the DFM system, didn't know this motor even had it. Couldn't feel it or see a readout at all. Got on the forum here and sure got interested, figured out how to monitor it. Pretty amazed to see it switching back and forth constantly, maybe 20+ times in a routine 10 mile drive. Then I saw an exploded view of the lifter and the little components inside. That is sure severe duty for that assembly. I thought it would be pure dumb luck if all those millions of lifters last for the life of the vehicle. Now we know. I signed up for the GMEPP real quick before the OE warranty ran out. Can't believe General Motors would put that crap in such a proven bullet proof motor.

 

[Z15]

A friend had his 2021 6.2L fail for the 2nd time, first time was Nov 2021 and they replaced 1 bank of lifters. Then last week engine started making noise and dealer said, lifters. So they tore it apart last Tuesday and found 3 collapsed, one of left bank (replaced before) and 2 on right bank. Theyreplaced all lifters. Btw, mandatory the oil is changed. SM told him these DFM lifters are the huge problem and driving them nuts and even into the 2022 model years they have seen failures. Only consolation is that recently the replacement part numbers have changed. If you got a 5.3: or 6.2L with DFM from 2019 up, its no if the lifters will fail, its when. Not enough 2023's out yet to say if they are affected.

PS - Mine have all been replaced recently........check engine light came on day while truck was warming in driveway. I looked at my invoice and I have the same lifter part numbers as Bob so hopefully what he was told is true, new part numbers-better part? Btw, he said he talked with salesman about tradein and they appear to not have any idea about lifter problems. Most probably don't even know what a lifter is. LOL

 

[DuraYuk]

Your experience as a tech gives you a helpful perspective on how GM and service departments handle failures in the fleet, and if your experience was in the last 15 years, then you likely understand the AFM system and its relatively low failure rate. So thank you for that and I find it reassuring that you don’t think there is a more serious systemic or design problem with the DFM engines.

All of that said, I have done enough reading and review of available information here and elsewhere to still hold the opinion that there is an underlying design and/or manufacturing problem with the DFM system beyond a faulty batch of lifters. Enough that I would not buy a current generation of this vehicle with a V8 until the problem is better understood and more permanent resolutions are available from GM or elsewhere. Nothing you’ve said so far is enough to change that opinion. I would want to see a more complete engineering analysis from GM or a reliable 3rd party, which we probably won’t have for some time.

While admittedly not a scientific approach to analysis, if your comparison to other potential failures were logical, I would still expect to see at least a few people here with water pump or transmission failures, but we’re not seeing that. Some transmission shifting problems, sure, but not failures. I truly don’t mean to be argumentative at all. Just trying to lay out my logic for thinking about it as a design problem.

All im saying is that I would have welcomed the messed up lifters because they are relatively easy and straight forward to change. Instead my time was spent doing transmissions (trucks, suvs, and cuvs), differentials , timing chains (3.6), water pumps (all models), and tcms/valve bodies. I did so much work we were audited only for the audit to find out its because we are a huge volume dealer so we would see the larger portion of failures.

I went to the gm training center to speak on the design failure of the wave plate as I was doing so many of them. And in some cases redoing the job after 30k miles because it would fail again.

The forums are not a conclusive research study as you see the problems people complain about. Many people will not get on here to complain because for them it's just an appliance.

Regardless of your opinion I still hold my experience as more valuable than a few disgruntled owners on the forum.

If you don't see value in that so be it. Doesn't bother me either way.

Wish you guys good luck in your vehicles.

 

[Seamus]

A few disgruntled owners?? Its much more than that, and its a huge issue. Your one tech in one dealer with that limited experience in that limited area, with a limited amount of these vehicles. Your opinion is no different that anyone else who has had the issue or who can read. BTW I have yet to see anyone with a 5.3 and a 6.2 and a bad water pumpon a new truck. The GM 3.6 nightmare motor has nothing to do with this motor. Counteless threads on many forums regarding this. Many here had to wait because parts were backordered it was such a prevelant issue.

I have posted this here before, I am one guy renting a 2021 suburban for a road trip. As I stood at the rental store awaiting the truck from the airport location, it arrives limping into the lot. New truck not many miles. Manager comes over, " we have to get you another truck, this one dropped a lifter"' HUH?? said this has happened a few times now, the new truck has an issue, wev'e seen several. This is one guy in one enterprise rental store. I go home awaiting the new truck and search the forum as we were looking for a new Denali. MANY posts on the issue. Few people are on forums...its a big issue. And as Geotrash stated above with 16 of these in there obviously the % goes up on the failure rate.

 

[DuraYuk]

A few disgruntled owners?? Its much more than that, and its a huge issue. Your one tech in one dealer with that limited experience in that limited area, with a limited amount of these vehicles. Your opinion is no different that anyone else who has had the issue or who can read. BTW I have yet to see anyone with a 5.3 and a 6.2 and a bad water pumpon a new truck. The GM 3.6 nightmare motor has nothing to do with this motor. Counteless threads on many forums regarding this. Many here had to wait because parts were backordered it was such a prevelant issue.

I have posted this here before, I am one guy renting a 2021 suburban for a road trip. As I stood at the rental store awaiting the truck from the airport location, it arrives limping into the lot. New truck not many miles. Manager comes over, " we have to get you another truck, this one dropped a lifter"' HUH?? said this has happened a few times now, the new truck has an issue, wev'e seen several. This is one guy in one enterprise rental store. I go home awaiting the new truck and search the forum as we were looking for a new Denali. MANY posts on the issue. Few people are on forums...its a big issue. And as Geotrash stated above with 16 of these in there obviously the % goes up on the failure rate.

It's just not as prevalent as you guys think it is. Its all anecdotal. Dropping a lifter while running is a safety issue potentially. If so many were doing it they would issue a recall. Nhtsa would investigate. We are only seeing a tsb on it. No wide range campaign.

A lifter is such a simple device. A pushrod engine is stupid simple. This isn't rocket science.

Regardless wish you guys luck. If you have one of these get it fixed and don't worry. If your worrying sell it and save yourself the strife.