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^ The BMW dealer where I bought my M5 and M Coupe let me freely wander the shop floor so I could visit with my tech friends. Over a few years I saw 20+ engines in both M and non-M cars with the heads off. In almost every instance there was (to me) shockingly thick carbon buildup on piston tops. No matter who I asked in the service department about these deposits the answer was always the same - "They all do it." My M5 was exactly the same at 37k miles...the heads were taken off and in spite of a history of alternating every 2k miles between Shell and Chevron fuels the piston tops were thick with carbon. There is no doubt in my mind the compression ratio is raised over time. If I go the Weistec head bolt route post warranty I''ll have them cleaned off for sure.
Yes, the black carbon deposits is normal, and can affect compression.
The use of E85, which i run in my Evo as well, cleans the hell out of everything and burns cleaner. Which is why cars running E85 have significantly less deposits.
Consider the low grade fuel we get, I'm not surprised by the carbon build up on both the heads and valves. Compression increases due to carbon build up is not unheard of but usually offset by the engine istarting have some compression loss through the compression rings and valves at the point in time. On old school carbueted engine, the carbon build up would remain as a source of ignition and since the carburator contain fuel in the bowls even after the engine was shut off, this would cause "run on" ie the engine continued to run until all the fuel in the caburator was burned off. It would seem a good idea to have a valve job done as long as the heads are off since most of the labor is taking the heads off. Not sure if bringing each piston up to top dead center would allow you to safely clean the piston tops off.
Here's a shot of my m156 pistons taken via an optical camera. Symptoms were that the car was pinging.
Had it removed and all was good.
I have a Wiestec Oil Separator installed now and it catches a decent amount of oil, even though I NEVER need to top up oil between changes, it really doesn't use much at all.
Carbon deposits softned up by using engine cleaner
Can see here where an area was scraped off using a tool through the spark plug hole
Last edited by schmick325; Aug 19, 2012 at 06:43 AM.
97 audi s6,97 audi a4,05 audi a8l, new owner of a c63 amg
:0 should i or shouldent i take deliver of my c63, if this is an ongoing issue i dont want to run into trouble after owning my car for only a few months! buying preowned 09 c 63 amg with perf package 100,000km
This is a very interesting thread, thank you for posting all those detailed photos! How has the engine been running after the repairs? That is if you still own the car
I find it funny that someone worries about a dealer tech doing some work. And here it looks like the factory tech didn't get the con rods positioned correctly. Arrows are pointing to the rear. Or just more goofy Mercedes stuff and they are supposed to be pointing at the joining areas. Since on the youtube video the other side they point to the front as well as the last photo here.
Very cheaply made engine, and way over priced
Last edited by exhaustgases; Sep 26, 2017 at 08:42 PM.
fyi, your car is a p30 pack, p31 didnt come out untill late 2011 models.
Originally Posted by cek
I waited to post this until I had gotten my car back from the dealer and was fairly confident that all had been rectified. After a few hundred miles of hard driving I think I'm ok now...
I'll kick off what I expect to be an epic mbworld C63 thread with this shocking picture. What you see here is the left cylinder head of my M156. The green stuff is coolant that has seeped through the WALL OF THE HEAD.
Coolant leaks due to porosity of aluminum heads is not unheard of. From my (limited) research I have not found any instances of it happening on AMG cars and the tech at the dealer said he'd never seen it before either.
As you know aluminum heads are forged, and forging results in material that is porous to a degree. During manufacturing, flaws in the forging process can cause extreme porosity. For this reasons heads are pressure tested before installation. In some cases (mine, apparently) the heat cycling of use can cause heads that are on the margin to 'open up'.
After cleaning you can see the two pin-holes in this picture (pretty much dead center):
This head has been replaced and the bad one has been sent back to AMG in Germany for investigation. I doubt I'll ever hear any results, but boy, would I love to.
But wait. There's more.
This seepage was only visible to the tech because the engine had been removed from the car, enabling him to see it. Why did my M156 need to be removed from my 2010 C63 with 15,000 miles on it you ask?
Stay tuned and I'll tell you...
f
p30* , p31 has silver heads and added more power 2011 and up. From the pics your car has a base motor not a p31, 507 or bs motor that is given in the upgraded p31 package.
f
p30* , p31 has silver heads and added more power 2011 and up. From the pics your car has a base motor not a p31, 507 or bs motor that is given in the upgraded p31 package.
It's a p31 the guy literally has his purchase thread linked in his sig. The P31 began about halfway through model year 2010.
Good to see your first post in 2.5 years was a response to a five year post and you aren't even right. See in you 2019!
My 2012 coupe has leaking upper oil pan and bed plate to block too now. At 75,000 miles. I normally wouldn't have mentioned this here since this must be getting more common as time goes on, but Torsten has his name on my engine as well! Just gave me a chuckle is all really.
I'm not even going to think about fixing it until it's bad enough to hit the floor though. And even then will probably keep the level topped off for quite some time before splitting the case.
Just sad when the car goes from being 0 problems to being a dirty old man.
My 2012 coupe has leaking upper oil pan and bed plate to block too now. At 75,000 miles. I normally wouldn't have mentioned this here since this must be getting more common as time goes on, but Torsten has his name on my engine as well! Just gave me a chuckle is all really.
I'm not even going to think about fixing it until it's bad enough to hit the floor though. And even then will probably keep the level topped off for quite some time before splitting the case.
Just sad when the car goes from being 0 problems to being a dirty old man.
Your engine has been apart by the looks of that silicone gasket goo hanging out the sides.
Your engine has been apart by the looks of that silicone gasket goo hanging out the sides.
While I have no way to confirm or deny what may have been done on this car, I was under the impression that a little bit of ooze is how they all leave the factory. No goo at all or a big glob all the way around would ring more alarms for me.
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
See in you 2019! 
Just gave me a chuckle is all really.
