2010 E63 Head Bolt Failure
 

Hey Everyone,

I wanted to share my recent experience with my 2010 E63. I purchased the car in 2014 with 16k miles on it; the car in general has been awesome which was the reason why I purchased the vehicle. In 2015 with 20k miles on the odometer I received a check coolant level message which was concerning to me; I had lost about 100-150ml. I sent the car to the dealer and had them check for leaks or loose hoses. They weren't able to determine the cause of the coolant loss; which is when I started researching potential issues with the M156 engine. With the help of this forum I discovered the dreaded head bolt issue; I ran a check on my VIN and it was within the affected range. I had the dealer run a compression test for good measure and everything was withing normal tolerance. I then called up MBNA to see if they were willing to provide goodwill assistance to get the head bolts replaced at the dealership (the original quote was $5k).
They refused to do anything and their reasoning was
a) I was the second owner of the car
b) this is a preventive repair which may or may not be needed in the future.
Mercedes Benz of North America does not acknowledge that these engines are plagued with faulty head bolts which may lead to catastrophic engine failure.
I refused to sell the car at that point and decided to keep a close eye on it by regularly checking coolant levels, and getting my oil analyzed by Blackstone Labs with every oil change. Fast forward to March of 2018 with 66k miles on the engine; I had another check coolant level warning and then the engine would shutter from time to time when the oil temp reached 220F-230F however no fault codes were thrown. In May I decided to take the car to the dealer to get it diagnosed again. Here's the dealer's notes on what they discovered:
"COMPRESSION TEST. WITH ENGINE HOT, REMOVED ALL
CYLINDERS, REMOVED ENGINE OIL CAP AND COOLANT RESERVOIR CAP (COOLANT LEVEL
SLIGHTLY LOW) AND SPARK PLUGS. PERFORMED COMPRESSION TEST AND ATTACHED
RESULTS, CYLINDER 6 IS THE LOWEST AT 14.6BAR WHILE THE OTHER ARE AROUND 15.5BAR
(2BAR PERMISSIBLE DIFFERENCE BETWEEN CYLINDERS). PERFORMED CYLINDER LEAKAGE
TEST, ALL OK AT 1% LEAKAGE. USING BORE-SCOPE CAMERA, INSPECTED THE PISTON TOPS,
FOUND BANK 1 (CYLINDERS 1-4) HAVE A NORMAL BLACK CARBON BUILD UP COVERING THE
SURFACE OF THE PISTON TOP. PERFORMED SAME INSPECTION ON BANK 2 (CYLINDER 5-8) AND
FOUND CERTAIN SPOTS ON THE PISTONS ARE PERFECTLY CLEAN. SUSPECT HEAD BOLT
DAMAGE CAUSING COOLANT CONSUMPTION AND THUS CLEANING OF THE COMBUSTION
CHAMBER AND PISTON. RECOMMEND REMOVING THE VALVE COVERS AND CHECKING
CYLINDER HEAD BOLTS AND MOST LIKELY REMOVING THE CYLINDER HEADS AND REPLACING
GASKETS AND BOLTS."
I tried going down the MBNA path to see if they would at least now acknowledge that this issue is not normal for a car of this age/mileage; well that was a waste of time and energy! The dealership provided a 10% discount on the $5k repair but I felt that wasn't good enough. I did some research on some independent Mercedes repair shops in the area and found a place that was highly recommended and quoted me $3k. I decided to send the car to them and have them go through with the repair. The first test they ran indicated a head gasket/ head bolt issue when they found exhaust gasses in the coolant system. This test along with the compression test concluded that there was in fact a head gasket issue. They have been working on the car for the past few days now and are about to deliver the car to me today. Throughout the process they have been sending me regular updates and photos of their work as they progressed throughout the repair to keep me informed which I thought was a nice touch. Please see their photos below:
https://cimg2.ibsrv.net/gimg/www.mbw...862ead9c96.jpg
https://cimg9.ibsrv.net/gimg/www.mbw...f72b831fe0.jpg
https://cimg5.ibsrv.net/gimg/www.mbw...1496db5b2a.jpg
https://cimg1.ibsrv.net/gimg/www.mbw...2e79362e41.jpg
https://cimg8.ibsrv.net/gimg/www.mbw...eddc6ea2cc.jpg

I'll provide additional updates once I get my car back, but long story short I'm glad I was able to detect this issue before losing my engine.... oh and MBNA is useless!

Did the oil analysis ever point to a problem? Like, finding excess coolant in the oil?

Have the shop inspect the cams and valve buckets too ,those engines are known to eat camshaft lopes.

x2

also....red coolant? I thought it would always be that blue colour for all Mercedes? Or perhaps it's a different colour/type due to climate/region?

When was the last oil change and then oil analysis done, vs the date of failure, ie March 2018?

Hey Omega_Jeff, no there were no traces of coolant in the oil however the independent shop analyzed the coolant and found a presence of exhaust gasses which indicated a head gasket leak... Its a pretty simple and quick test.

@ Celicasaur-The coolant is the Blue antifreeze, perhaps its climate/region dependent. The oil change was done and analyzed less than 500 miles after the head bolt issues was discovered all within a month.

Quick update on the status of my E63; the repair was successfully completed. The head bolts were replaced with the revised OEM bolts, the cam lobes all looked good, spark plugs were all replaced for good measure, one valve tappet was replaced and a coil pack as well. I suspect the shudders/misfires I was sensing was mostly caused by the faulty coil pack. I also had to reset the transmission's adaptive learning. As of now, the car feels responsive and I have not had any issues since the car was delivered to me this week.

Any reason why you didn't you replace all of the hydraulic lifters/tappets to the revised ones? Really easy change if you're pulling the heads.