Jump to content

Cylinder Head - Valve - Lifter / Lash Adjuster Replacement on new 2021 Tahoe Z71

Rich Hanley
 Share

Recommended Posts

newdude Senior Enthusiast

newdude

Posted
Posted (edited)

No, you didn't get a lemon. 

 

Yes, there has been a rash of AFM/DFM lifter failures in the past year.  Dealer will fix it and it will be all good again.  Typically its a lifter or lifters, plus any bent pushrods.  If you have a cylinder fail on each bank, dealer will replace all 16 lifters.  If one bank had the failure, that entire one bank will get 8 lifters.

Edited by newdude
Acey76 New Member

Acey76

Posted
Posted

Happened to me around 5,000 miles.  2021 Suburban z71 5.3.  

 

First time left bank, 3 weeks later right bank..  

 

Almomst 3 weeks in the shop.

 

Seems to be good now!

newdude Senior Enthusiast

newdude

Posted
Posted
17 hours ago, Rich Hanley said:

Pretty severe bend in the push rod. Is there a way to disable the DFM system and/or is GM issuing a recall?

 

 

 

No recall.  Not sure what GM has layed out for any plans other than fixing the ones that break.  

 

None of the AFM/DFM disable devices work on Tahoe/Suburban/Yukon/Escalade.  These SUV's are on GMs all new Vehicle Intelligence Platform or VIP which replaces Global A architecture for vehicle electronics and module communications.  The ECMs have not been "cracked" if you will, nor has anyone validated fitment of devices like the Pulsar LT to work.  

  • 2 weeks later...
Cantrell Enthusiast

Cantrell

Posted
Posted

There is another thread on this.  It speaks to the errors that are shown when this happens.  My truck has been at the dealership for over a month now.  Still waiting on parts.  There is nothing I or they can do but wait on GM to deliver.  The sad thing is that they knew exactly what was wrong when I dropped it off.  

MAC21 Enthusiast

MAC21

Posted
Posted

Been in for 21 days now.  Just hear from dealer. Parts will be in tomorrow.  Replacing all 16 and guides.  Looking forward to having my brand new truck back!  

Cantrell Enthusiast

Cantrell

Posted
Posted

I just got the call from the dealership.  My truck is ready.  I stopped by there the other day and spoke to the technician.  He had them order parts for all cylinders so the top of the engine was completely tore down while I was there.

GM suggested that I test drive the truck with the technician so I could point out anything that I thought was not normal.

I also spoke to GM about lemon law and options.  They said they were working on rebuilding trust in GM vehicles and were willing to discuss reimbursement option if I decided not to follow the lemon law route.

 

If all is well and accepted, it will have been at the dealership for 38 days.

Rich Hanley New Member

Rich Hanley

Posted
  • Author
Posted

Make sure they put a new serpentine belt on after the repair. The dealership did not do that for my vehicle and that left us stranded on the highway for 5 hours in 100 degree weather waiting for a tow truck. Not to mention the $800 for towing, lodging and repair at another Chevrolet dealership. Could have easily been avoided…

Cantrell Enthusiast

Cantrell

Posted
Posted

They did not put a new belt on.  What would warrant a new belt?  I am not at all saying you are wrong.  Just curious why?

 

Cantrell Enthusiast

Cantrell

Posted
Posted

GM is offering me compensation.

Just not sure if I should try to lemon law my truck, even though I guess it is fixed now.

Or, maybe try to exercise a buy back or something like that.  Only problem is, trucks a pretty slim pickens right now.

Rich Hanley New Member

Rich Hanley

Posted
  • Author
Posted
1 hour ago, Cantrell said:

GM is offering me compensation.

Just not sure if I should try to lemon law my truck, even though I guess it is fixed now.

Or, maybe try to exercise a buy back or something like that.  Only problem is, trucks a pretty slim pickens right now.

What is GM offering you?

 

1 hour ago, Cantrell said:

They did not put a new belt on.  What would warrant a new belt?  I am not at all saying you are wrong.  Just curious why?

 

If they 

  • 1 month later...
5rings New Member

5rings

Posted
Posted

just wondering if folks have heard of offers from gm "to rebuild trust".  my z71 is in the shop for 14 days now. broke down with lifter problem and cyljnder misfire at 10000 miles and while we were on a 2 week road trip. 

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Latest Articles

  • Posts

    • James Beyer
      Trading 7.3 (Godzilla) for G.M.C gas

      By James Beyer · Posted

      Congratulations Isttype, on your gmc. Really like my 2024 2500hd sle doublecab now with 85,500 miles.  I checked the oil today at 4800 miles since last oil change and barely reading on the stick.  I don't care if GM says it's Acceptable adding a quart every 2000 miles because that is 100% BS, It is not a 1966 Harley Shovelhead! Sounds like it's setting up a future failure like I had with my 1500 6.2l. Other than oil consumption problems, I really like the 6.6l gas and 10 speed is really nice.  Towed a light 4000 pound trailer last week and averaged 14 mpg.  I was pretty impressive that a 7300 pound gas truck did 14mpg towing, Later-
    • Grumpy Bear
      OCI, not when but why?

      By Grumpy Bear · Posted

      Long Term Cold Cycle Limited Testing   Back to the 1990's and XOM's million mile test. Since then there have been others and there will be more. Schaeffer's, AMSOIL to name two. Of these Schaeffer's is the stand alone which I will explain in a bit later.    http://papers.sae.org/600190/:   http://papers.sae.org/850215/:   Up to 75% of  engine wear occurs on cold starts. These two links (above) provide the technical reasons for engine wear. In a nut shell, and by a large margin, cylinder wear is what takes out most motors and even with a pre-oiling system that part of the engine is dry enough on cold starts and cold warm up to pierce Stribeck.   So when you put a motor, or a car, on a dyno for a million miles stopping only for oil changes, (yes fuel is uninterrupted) or break down maintenance, you are depriving the test of the most important part of it's wear cycle. Yes a million is then a pretty easy walk even for a mineral oil under those conditions.    How about cleanliness during the long test cycles? Same thing. Varnishes that stick rings and insulate parts are laid down by repetitive 'heat cycles'. It's the cool down the precipitates the varnishes. These long runs also hinder acidic attack caused by cold start richness and less than optimal cold start ring sealing. They hinder water formation and enhance breathing of the crankcase; the petri dish of acid formation, the first step in sludge formation, amalgamation and precipitation. These motors are also monitored and controlled for water and oil temperatures to within the "normal operating range".      https://www.swri.org/sites/default/files/sequence-iiih-test.pdf Note the test sequence in some boutique oils literature for testing, API IIIH, is not the standard used for the ILSAC G7 testing. Does that mean it is irrelevant? No, not as used. As used as a 'visual guide' it makes it's point. The G7 weighted piston deposit minimum is lower.      Back to Schaeffer's. That was a cyclical test of an engine in fleet service and not a dyno mule and if you saw the video it was not mirror clean but wear was low.    There are oils like BioSyn and other 'Renewable" source oils that taught cleanliness and have proven themselves in fleet testing. Havoline an other example.    The newest ILSAC G-7 test prioritize cleanliness, LSPI mitigation and fuel economy OVER WEAR. In comparison Porsche C30 Specification Verses ILSAC G-7 Specification below:      Some will balk that this graph isn't apples to apples and I will challenge that in that this graph represent the SPECIFICATION and not the any One Oil Performance.   It is absolutely possible to minimize wear, maximize cleanliness and mitigate LSPI etc., It just isn't cheap and currently I see none that are not walking toward profit over performance.     
    • asilverblazer
      Intermittent no-code issues on 2022.5+ V8 trucks — what did the shop fail to capture?

      By asilverblazer · Posted

      I don't think you will need a split, separate product, etc., the OBD port should be able to deliver everything you need. Since your device would be plugged into it all the time, it wouldn't miss anything.    Hardware in this case will be the easiest part of your project - ELM 327 devices will already deliver all the data you need. Reporting/software is where your advantage/marketability is.
    • Coastie05
      2027 GMC Sierra: Official Discussion

      By Coastie05 · Posted

      I do too. I’ll never be stuck again 😂
    • KARNUT
      2027 GMC Sierra: Official Discussion

      By KARNUT · Posted

      It has happened to me a few times. I carry a jumpstart-tire inflator with me.

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...