Think my LT1 is blowing up. Lifter issue
 

Long story short, I took my car to the dealer about 2 months ago because I heard what sounds like a clank/knock on cold start and restarts if it's been sitting about an hour. It's definitely not the DI, I know what that sounds like. The dealer told me it's normal, nothing to worry about, just how these engines are.

Then I read a post here a few minutes ago that said he had the same thing and his motor imploded. So I go outside, at 2am, and shoot these videos.

https://youtu.be/0xcwPPBzpn8

https://youtu.be/ZVnOQVbnZMA

Sounds bad right? Then I find this TSB about this exact F****** issue.

https://gm.oemdtc.com/3656/15-06-01-...-chevrolet-gmc

I'm fuming now and will be driving straight to the dealer in the AM.

Yep, this is exactly how my motor went
 

Gm isn't admitting it but there is a major issue with the afm. My car sounded exactly like yours does and the whole motor was toast. Just do yourself a favor after the put your new motor in. Check over ever inch of your motor. I found all kinds of loose things and bolts missing. Oh and check your oil level. Apparently that's an option with a new motor lol. My dipstick was completely dry. Cars being towed back in for possible damage to my new motor. I'm in the process now of getting a lawyer.

Wow, I'm hoping its an end-of-production-run issue where machining tolerances were out of spec.

I'd hate to hear that its a true Materials' failure. That's going to affect a whole lot of engines..

Thanks for posting Guys

More damage? I just dropped it off now. Gave them the bulletin number and then I played the video. The advisor heard it and concurred. Hoping it isn't too far damaged yet. I have noticed a slight decrease in power from when I first bought it but nothing drastic.

A deep knocking sound like that would make me quite a lot more nervous than a ticking sound would.

So you hear it to right? I'm not just paranoid? It's mostly there when cold or after sitting about an hour. Then it comes and goes.

Wow, I can't believe this is still happening in Gen 6!!!

There was a TSB for early Gen 5 L99 engines, and I had the AFM lifters replaced with a supposedly improved design. It's been quiet and trouble free for about 30,000 miles now. The dealer put his most senior mechanic on this, and everything was right and tight when he finished. This is not a minor project. To take the heads off, a lot of hoses and cables get disconnected. Orderly and clean work is required. I can see this being a problem at many dealers.

So why is the problem back again? Sorry to hear!

That is not a tick. That is LIFTER KNOCK! New crank/valve train/lifters for you. Hopefully they replace the whole engine. What year is your car? What is the vin? How many miles have you driven it in its crippled condition?

Can this happen on an M6?

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It seems it's not just the camaro that's affected, and not just the 6.2l engines. It would appear that many models in the GM lineup with AFM are affected according to the tsb.

Yes. It's the engine, not the transmission. Ticking that is constant and consistent and increases/decreases with rpm is normal for DI. My LFX did it, my R60 did it, and now my LT1 does it. But in OP's video, you will hear a loud inconsistent KNOCK, accompanied by other horrible sounds.

Dang, hasn't happened to me yet, but this sucks

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I'm mad. I paid good money for this car2017 it has a total of 13k miles and at least the last 4 have been driven with this. I've noticed a slight loss in power recently but not huge. It still pulls well but I remember it pulling harder brand new.My car is an M6.Damn it. I'm so mad. I told them about it and they originally came back "oh that's normal". Against my better judgement I said "ok they are they techs" knowing full well that it sounds like knock.Hope it doesn't.

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Damn 4k miles with a lifter that sounds that bad? Even with the issue, gotta say these are tough engines. They'll take care of you OP, thats what the warranty is for! It sucks though that the dealership thought it was normal. Go somewhere more competent for the repair, anyone who calls themselves a technician or mechanic that hears that sound and declares it normal, needs to be educated. If they replace your engine, make sure they put OIL IN IT.
Would you mind giving us the vin? I'd like to know how close your car is to mine assembly wise. And I'm sure others here would also like to know.