GM service bulletin for faulty valve springs

polarys425 · November 6, 2020

Goes thru Oct 7 production date now.....

Transient · November 8, 2020

https://gm-techlink.com/?p=13855

Goes thru Oct 7 production date now.....

Damn! I'm thinking I dodged a bullet with my 6/20 build date. 6900 miles on the truck, and nothing so far.

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Terry Swensen · December 6, 2020

On 10/6/2020 at 8:50 AM, RLW59 said:

I agree that a bad batch of parts can happen, I understand that, what I take issue with, is the replacement of just the one valve spring, knowing they cannot identify which ones are bad. GM should do the same procedure on all engines that have the failure, and that is replace them all, so that I/we do not get to experience the issue, over and over. I begged the dealership to replace them all on the first failure, at 60 miles. GM would not allow them to do so.

This is my second bad experience with a GM product in the past 4 years (life long GM owner), the other was a 2016 Tahoe they never could fix. The dealership helped on that one, with a great deal on a trade in. I think, they did so, just to get it out of the service area, where it resided most of the time. I will say, the dealership has been great, and the reason I stayed with another GM product. I did not go with RAM, because I thought the GMC would be more reliable. Hopefully, it will be in the long run.

It was an 8/20 build. I would be cautious with any 6.2 built in the time frame of the TSB right now.

Mine was built at the same date. 900 miles so far and no issues. Just wondering,was your built in the U.S. or Mexico? Don't know if it makes any difference but it's possible I guess.

RLW59 · December 6, 2020

2 hours ago, Terry Swensen said:

Mine was built at the same date. 900 miles so far and no issues. Just wondering,was your built in the U.S. or Mexico? Don't know if it makes any difference but it's possible I guess.

Truck built in Mexico, engine and trans in the USA.

PuffDr4gon · December 7, 2020

Is there any pre indicators that might happen prior to full failure? I have a 21 LT trail boss with 6.2L.

Yesterday, I had a loud tactile pop occur while backing out of the drive way. Almost like an acorn landing on the vehicle but way louder. I checked everything and nothing hit me. It then happened later in the day. 2 incidents same day. Has not happened again the last few days and I can't reproduce the noise.

Thoughts?

Supercup · December 8, 2020

Interested in figuring out the build date on my truck - anyone able to direct me to source for that. Traded my 2019 AT4 for a 2020 to get trailer tow mirrors - in August 2020. So far have 3,000 miles - no issues - but would be interested to know if it was built before the June date. Would hate to get stranded towing with the Family.

Also in reading through thread seems like a lot of failures within a few hundred miles of new - any failures with higher mileage trucks?

Edited December 8, 2020 by Supercup

Terry Swensen · December 8, 2020

17 hours ago, Supercup said:

Interested in figuring out the build date on my truck - anyone able to direct me to source for that. Traded my 2019 AT4 for a 2020 to get trailer tow mirrors - in August 2020. So far have 3,000 miles - no issues - but would be interested to know if it was built before the June date. Would hate to get stranded towing with the Family.

Also in reading through thread seems like a lot of failures within a few hundred miles of new - any failures with higher mileage trucks?

Your build date is on the inside bottom of your driver's door frame. I've seen a 1200 mile truck have this issue. There's probably more out there but unless you see posts online somewhere,you don't here about it.

My build date is 8/2020 and have had no trouble yet at 900 miles while a same truck built at the same plant with the same build date had a broken valve spring.

Edited December 8, 2020 by Terry Swensen
Wrong word

Larry CG · December 9, 2020

10/31 build date on 2021 AT4 6.2L. been in shop for three weeks and counting while they "figure it out." There are more out there. Happened to my cousin's neighbor... tow truck guy that picked mine up said he had five that week. Turn over more rocks and I guarantee there are more. Check out the 'vette forums, too.

steelcity · December 9, 2020

4 minutes ago, Larry CG said:

10/31 build date on 2021 AT4 6.2L. been in shop for three weeks and counting while they "figure it out." There are more out there. Happened to my cousin's neighbor... tow truck guy that picked mine up said he had five that week. Turn over more rocks and I guarantee there are more. Check out the 'vette forums, too.

10/31? Affected build dates were supposed to be June 1st thru September 15th?

Larry CG · December 9, 2020

2 minutes ago, steelcity said:

10/31? Affected build dates were supposed to be June 1st thru September 15th?

Date on truck, per dealer. If that is when it came off the line then even more disappointed. Not convinced problem is isolated, but don't have much to go on, either. Hence, trying to educate myself.

Supercup · December 9, 2020

17 hours ago, Terry Swensen said:

Your build date is on the inside bottom of your driver's door frame. I've seen a 1200 mile truck have this issue. There's probably more out there but unless you see posts online somewhere,you don't here about it.

My build date is 8/2020 and have had no trouble yet at 900 miles while a same truck built at the same plant with the same build date had a broken valve spring.

Thanks - did not see those two tags when i looked last night in dark. Mine was 7/20 build - is a late 2020. So right in the middle of the time frame - 3,000 miles so far - no issues - goes into dealer tomorrow for fluid service

Terry Swensen · December 9, 2020

57 minutes ago, Supercup said:

Thanks - did not see those two tags when i looked last night in dark. Mine was 7/20 build - is a late 2020. So right in the middle of the time frame - 3,000 miles so far - no issues - goes into dealer tomorrow for fluid service

You might express your concern to the service manager just to see what there response is. That's what I'm planning to do when I take mine in the for the first oil change.

Supercup · December 9, 2020

I did this morning when I dropped the truck off - this particular GMC dealership Mgr. in South Orange County CA told me they had not had a single case yet they had addressed, and was unaware of the issue.

So for now I will just enjoy my track and keep my fingers crossed!

Terry Swensen · December 9, 2020

1 minute ago, Supercup said:

I did this morning when I dropped the truck off - this particular GMC dealership Mgr. in South Orange County CA told me they had not had a single case yet they had addressed, and was unaware of the issue.

So for now I will just enjoy my track and keep my fingers crossed!

Wow, amazing. Funny but that's the same thing mine said about the collapsed lifter issue on my 2008 Silverado. He said he had never heard of any problems. Must be the required response. Plausible deniability.

Transient · December 10, 2020

Wow, amazing. Funny but that's the same thing mine said about the collapsed lifter issue on my 2008 Silverado. He said he had never heard of any problems. Must be the required response. Plausible deniability.

That's exactly why I print TSBs i find on my vehicles. The service writer or service manager tries that line and I'll pull out the TSB and tell them they have now heard it.

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