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600 mile 2020 6.2 collapsed lifters


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About 2 weeks ago I purchased a 2020 Sierra 1500 AT4 and just recently upon coming up to 600 miles on the dash I quickly noticed loud ticking noise coming from the engine area. Brought it in for service.

 

next day I received a call in the morning stating that multiple lifters Have collapsed. Was told they will swap them out on the entire side and was told they’ll get it taken care of. 
 

picked up my truck after hours and the noise was the same. Maybe even possibly worse. Needless to say I put the keys back in the box and went back home. 
 

I see people on the forums have ran into similar issues but I don’t see how it was rectified in the end. Should I be getting or requesting a new motor? Is my motor just a lemon? Or is there a simple fix? I’m waiting to hear back from the dealer now.

https://youtu.be/sNbxbzToWPI

 

https://youtu.be/IC5XqTUlEI4

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.02

 

If the problem was collapsed lifters and they were replaced and the noise still exists - two possibilities: either they didn't replace them;  or they did replace them but they did not fix the underlying cause that causes the lifters to collapse.

 

Unlike some '19 V8s and prior AFM engines which use a LOMA manifold to determine when and which lifters collapse to deactivate a cylinder; all the '20 6.2s are DFM engines which do not use the LOMA manifold but instead individual solenoids to control oil flow to the lifters to activate/deactivate a cylinder.

 

Failure of the ECM to trigger the oil solenoid will starve a lifter of oil and it will collapse. .....so even if the lifters are good they will collapse without an oil flow. And the odds of simultaneous failure of multiple lifters on only one bank seem great......but lack of oil flow due to a blocked oil gallery or electrical feed problems to the solenoids in one bank can oil starve the lifters and give the same results, i.e. a good lifter without an oil supply will collapse. It appears, further diagnosis is necessary with the electrical and hydraulic systems before you can properly diagnose an infant mortality multi lifter failure. And failure to fix the problem after replacement with all new lifters leads one to believe that the problem ain't with the lifters..

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The Silao plant currently produces the following vehicles and Propulsion Systems:

  • Vehicles:
  • Propulsion Systems Assembly
    • V-8 engines, including:
      • 4.8L
      • 5.3L
      • 6.0L
      • 6.2L
      • 6.2L supercharged
    • Transmissions for rear-wheel drive vehicles, including:
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A bad gasket can cause lifters to collapse!?  What are these engines made out of, cardboard!?

I think he meant they had to tear it apart again because they used the wrong gasket AFTER the lifter repair.


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21 hours ago, Colossus said:

A bad gasket can cause lifters to collapse!?  What are these engines made out of, cardboard!?

My .02 guess is good gasket, bad bolts..... or new bolts and tightening technique.

 

Nothing wrong with the engines or components.....it's the technology and having proper replacement parts and trained and equipped personnel. These aluminum engines require special alloy head bolts which "stretch" when torqued to provide a spring action during expansion and contraction to properly seal oil pressure within the  galleries for operation of the hydraulics, including the lifters. The tightening order, and a mandatory tightening sequence of torque plus additional angle is required.........original bolts must be thrown out and new ones installed each time a head is removed....try to kludge it and use the "stretched" ones and you are looking at an eventual leak

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