M156 head bolt problems
The understanding has been that all 08-09 C63s have the old headbolts, and that a significant number of 2010s do as well, but that the 2011 models are safe. The engine number cutoff is 60658.
I previously mentioned that I had not found a 2010 with the new headbolts, and I just found something a bit uglier:
I ran the VIN of a 2011 C63, reflecting a delivery date of 07/06/2010 in EPC. This car has been identified as a 2011 model in both autocheck and carfax. Anyone want to guess which side of 60658 it sits on? I'll give you a hint, it's below 60500.
In conclusion, ALL 08-10 C63s have the old headbolts, INCLUDING very early 2011 models.
The Best of Mercedes & AMG
Did you have issues or was this preventative maintenance,
Looks like you got a few to do, which car did you a test run on.
Were any bolts broke or did you see any offset washers surfaces?
Any old style bolts that were or seemed to be torqued more than the others?
Any issues with holding cam timing?
Did you apply any sealant to the lower thread area on the new bolts and lastly was there any sealant seen on the old bolts that you removed.
Did you do replacement in any particular order, ie torque sequence.
Must have been a good feeling when you buttoned her up.
Again congrats.
Karl, We have heard this before , but no one has produced a DIY, even in text with out pics would help. Are you up for it? motoman
I did it for preventive maitance .
Renntech talk with AMG and did the work.
The next question is how much did cost?
I will have to get back to you on that.
The cams have to be removed. You need a special mb tool that holds the cams in place to put them back. Also one cam needs another special tool to hold it with the adjuster, the other cams you can use a bolt that threads into both gears.
Once you remove the cams and put them back in, it's quite simple. It's just getting over that first hurdle.
It took us 2 days to replace all the bolts with studs. No way would I use the new mb bolts.m if your going that far use the studs and do it right.
What's your take on the "discovery" that 2010-2011 years also have the weak headbolts. motoman
Last edited by motoman; May 20, 2013 at 11:52 AM. Reason: block thread sealing
The oem bolts are a one time use only. Studs can be used numerous times and have more clamping force.
2010:
WDDGF7HBXAF440386
WDDGF7HB6AF494364
WDDGF7HBXAF440386
WDDGF7HB5AF446287
WDDGF7HB8AF483933
WDDGF7HB1AF374732
WDDGF7HB1AF431737
WDDGF7HB6AF471070
2011:
WDDGF7HB7BF588559
WDDGF7HB6BF539448
WDDGF7HB4BF585313
WDDGF7HB5BF553387
WDDGF7HB5BF656647
WDDGF7HB9BF528816


You don't need to pull the head to switch bolts/studs.
It has nothing to do with building an engine. Your simply switching fastners.








all the reading made me miss read the numbers that were posted. 
