Greetings fellow auto enthusiasts! Hoping for some advice. Working on my 2010 c63 AMG with the m156 6.3L V8. At the 100k miles mark and decided to replace the head bolts and rebuild the entire valve train, (new cams, adjusters rebuilt, lifters, etc) With the heads still on, I pulled the plugs and scoped a few cylinders and see quite a bit of black carbon built up. In some areas it almost looks like layers of it could flake off. My question is, how should I address this and do I even need to? I’ve read that trying to remove it could make things worse due to bits and pieces coming loose and potentially getting into places they shouldn’t be. I’ve also read I can just use an additive and run the engine harder to help burn off some of this. Or, should I just leave it be?
by Benzdrivingguy
![[1987 Penske PC16] in Australia](https://www.evshift.com/wp-content/uploads/2026/01/ftjw4f9f7pdg1.jpeg "[1987 Penske PC16] in Australia")
3 Comments
Injector cleaner and Italian tune-up. Not really that much else to do with the heads on.
Most shops will sell an induction service, they spray a chemical through the intake with the engine running and it’ll burn the carbon off. You can also try sea foam. You attach a straw to the sea foam can to the engine (instructions vary) and it’ll suck the sea foam in and burn off the carbon.
Before tear down I would run fuel injector cleaner through it and do a fuel induction cleaning service. And if I was tearing it down to replace the head bolts I do the valve train that would be pulling the heads and that’s a perfect time to clean everything. It’s going to take time but if you’re that far in might as well clean everything.