2021 6.2 engine knocking

Bob’s Sierra · May 4, 2021

I have a 2021

6.2

at4

that I bought new in January

experienced severe engine knocking yesterday

took it in to dealer I bought it from and they think it maybe a stuck lifter

but they don’t know for sure

very very frustrating

could be 7-10 days without my truck

anyone seen this ?

newdude · May 4, 2021

Yes. You aren't the only one. 4000 mile Tahoe sitting outside my view here at work getting all 16 lifters and 4 pushrods right now. Lost a cylinder on each bank.

GM has dealers replacing all of the lifters on whatever bank(s) there are failed cylinder(s). You will get it back and it will be good as new.

Edited May 4, 2021 by newdude

Bob’s Sierra · May 5, 2021

Thanks for the reply

Joe Clarke · May 10, 2021

Having the same problem with the 5.3. Only 2300 mile on it. I was told that GM knows they have a problem. As a result there are no parts available because so many truck across the country are breaking down. I was told that they have know idea how long the truck will be down.

Bob’s Sierra · May 14, 2021

This is their latest

response

“

Wellllllllll. We have some back ordered parts. We are searching the country for them now.

I made GM aware of the situation

Bob’s Sierra · May 14, 2021

Question

is this issue being caused by the afm?

if so if I get my truck back I’m thinking of Getting the pulse to disable afm

issue :

We are currently in the process of dismantling the affected side of the engine. We have had parts ordered for it. I should know more tomorrow.

Lifter, push rod head bolts and gaskets

BIGDOGx · May 14, 2021

On 5/4/2021 at 3:53 PM, newdude said:

Yes. You aren't the only one. 4000 mile Tahoe sitting outside my view here at work getting all 16 lifters and 4 pushrods right now. Lost a cylinder on each bank.

GM has dealers replacing all of the lifters on whatever bank(s) there are failed cylinder(s). You will get it back and it will be good as new.

Problem is they just get replaced with the same failing lifters, this has now been an issue with the 6.2 since 2014. Gm clearly has taken the we will just fix the broken ones instead of doing what's right and making a part that won't fail.

newdude · May 14, 2021

6 minutes ago, BIGDOGx said:

Problem is they just get replaced with the same failing lifters, this has now been an issue with the 6.2 since 2014. Gm clearly has taken the we will just fix the broken ones instead of doing what's right and making a part that won't fail.

5.3 as well, same lifters. Its not always the lifter's fault either. A mis-time of the VLOM/DFM solenoid can send or pull oil at the wrong time as well. The bulletin for 2014-2018 trucks they want all AFM lifters on the failed bank(s) replaced as well as the VLOM which now conveniently ships with AFM lifters in the box.

Edited May 14, 2021 by newdude

Bob’s Sierra · May 14, 2021

This best part is there are no trucks to replace my At4

it’s a standard bed which apparently over the last 7 years is frowned upon in a half ton

my truck is very specifically setup for what I do everyday

Bob’s Sierra · May 15, 2021

Since this latest generation I’ve had new standard bed z71 or x31

2015

130,000 miles

transmission replaced at 108,000 just out of warranty

2018

Z71

60,000 miles

no issues

2020

x31

32,000 miles no issues

and now this gem 2021 6.2

all others were 5.3

Larry Richardson · July 5, 2022

I bought my 2021 Chevrolet Silverado LT around April 2021.
Several days ago the engine started knocking when in operation start up and running operations. Oil levels good and not due for an oil change.

I paid a lot of money for this truck wondering if this problem been reported to GMC.

Its definitely problem they need to know about this issue.

I was so shocked when the Tow truck driver told me that he had to tow 6 of them in one day with the same problem as mind.

Edited July 5, 2022 by Larry Richardson

JimCost2014 · July 5, 2022

So, how about miles, engine, CEL's, loss of power, rough idle while "knocking", drop in fuel economy before it started?

Is your truck still under warranty, did you report it, or file a claim? Have you heard back from dealer? Do you really believe the tow truck driver, or was he just shooting the S**T with you?

Lots of pieces in each puzzle, much easier to solve when they are all there.