LT6 engine failures/problems
Instructor
Joined: Oct 2014
Posts: 100
Likes: 9
From: Woodlands Texas
My C6 LS7 started huffing a little blue smoke out driver side on startup at 36,000 miles. When we pulled heads found 2 exhaust valves on that side were very, very loose in the guides. Took them to a shop that specialized in LS heads and they confirmed this was a common problem (given the low production numbers of the engine), they had repaired a bunch of them. They had found brand new Z/28 LS7 heads on engines they were modifying with incorrectly machined exhaust valve guides. Most LS7 had no issues, but some ended up with incorrectly machined heads from the contractor in Canada. Chevy/GM fumbled this problem.
Burning Brakes
Joined: Apr 2014
Posts: 780
Likes: 176
From: MV CA
Smitty1966, I believe this thread was specifically created just for the LT6 motor which is in the new 2023 Z06, why you are posting about C6 when this is about C8 gen corvette. If I am wrong I apologias..
Drifting
Joined: Mar 2020
Posts: 1,718
Likes: 150
From: Central Florida
Drifting
Joined: Mar 2020
Posts: 1,718
Likes: 150
From: Central Florida
Teslarosa is not following up here. Hope his issue was resolved.
Just to reiterate, my '24 LT 6 was producing a loud ticking noise, apparently from a cam follower, hot or cold, coming from the drivers side bank of cylinders/ cams. The pico scan confirmed this graphically and the TSB was performed at the Daytona, Fl dealership (I took a museum delivery).
Results were a reduction of approx 60-70% in tapping intensity to my older ears. After repair pico scan showed improvement. Without getting pissy and complaining more about it and demanding a new engine, it seems like an acceptable fix to me after putting on another 400+ miles. LT 6's do make noise, different from pushrod engines. Actually a bit of sewing machine noise I dare say
. But again, my older ears are to blame here for any inaccuracies!
YRMV
Just to reiterate, my '24 LT 6 was producing a loud ticking noise, apparently from a cam follower, hot or cold, coming from the drivers side bank of cylinders/ cams. The pico scan confirmed this graphically and the TSB was performed at the Daytona, Fl dealership (I took a museum delivery).
Results were a reduction of approx 60-70% in tapping intensity to my older ears. After repair pico scan showed improvement. Without getting pissy and complaining more about it and demanding a new engine, it seems like an acceptable fix to me after putting on another 400+ miles. LT 6's do make noise, different from pushrod engines. Actually a bit of sewing machine noise I dare say
. But again, my older ears are to blame here for any inaccuracies!YRMV
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Drifting
Joined: Mar 2020
Posts: 1,718
Likes: 150
From: Central Florida
Quite a noticeable ticking noise you can easily hear from either of the rear wheel wells. GM's pico scan is an audio print out of engine "noises". Look for sharp, repetitive amplitudes on the graph. That's what will trigger the TSB routine be undertaken.
Mine didn't appear until 600-700 miles after the drive home from a museum dilevry..
Last edited by GatorsJMC; Apr 24, 2024 at 01:21 PM.
Drifting
Joined: Mar 2020
Posts: 1,718
Likes: 150
From: Central Florida
Team Owner
Joined: Feb 2013
Posts: 22,598
Likes: 14,555
Interesting... I wonder if it depends on if the engine has to be dropped or not. The cam cover gasket is reusable and the video I watched online they literally just back off the bolt and retighten it.
Drifting
Joined: Mar 2020
Posts: 1,718
Likes: 150
From: Central Florida
Come to think- bolts were not replaced. Seals were the back order item. Left bank only was done...
Instructor
Joined: Sep 2014
Posts: 219
Likes: 20
The first C8 where having problems with the transmissions and now the new hot rods are having problems with the engine. Grr GM get your act together! I am the old man that likes the old cars. They didn't break (as often) and when they did it didn't take two weeks for a record time repair.
I can't wait for the new ZR-1. I hope someone wants me to take it for a spin. Although, I hope I don't spin it! Thanks for sharing???
I can't wait for the new ZR-1. I hope someone wants me to take it for a spin. Although, I hope I don't spin it! Thanks for sharing???
Instructor
Joined: Sep 2014
Posts: 219
Likes: 20
I love all Corvettes and especially the C4 ZR-1. GM did an excellent job of testing the LT5 before it went into the new Z. Ford and GM use to do actual endurance testing with engine builders and drivers. Now we leave to the brilliant AI. Just a sign of the times. 180K price for a new hot rod and the engine blow. I hope GM gets in front of this. It been going to long. I hope to drive a ZR-1 soon!