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A curious M156 situation - Head bolts & Other stuff
Hi All,
I have a few threads here regarding a LONG standing random cold start misfire. Basically I would get cold start misfires for 10 seconds after startup, everything was perfect after that, and I replaced EVERYTHING it could have been chasing it down to no avail.
Here's the background: https://mbworld.org/forums/c63-amg-w...e-stumped.html
Here's where it all came to a head, and started on the path I'm on now: https://mbworld.org/forums/c63-amg-w...t-failure.html
I did a compression test, leak down test, and scoped the cylinders. Compression and leak down were great but coolant was observed in cylinder #2.
In case you don't know, there's a great FB m156 page operated by Barry at Eightysixed Tuned: search for 'Mercedes AMG M156/M159 Engine Owners Group' that I posted a long thread of my testing and teardown. Long story short, my engine number is 61,563 and I have the old head bolts and suffered a head gasket failure. Pictures here: https://mbworld.org/forums/c63-amg-w...ml#post8849331
While tearing down everything, I found some weird things that made me doubt if I have the original engine in the car, or how it could have been repaired. I made a youtube video to explain them all:
That engine has been worked on. You're over 900 engines built after they stopped using the old bolt design.
I would agree...but...could you even buy the old style headbolts after 2011 from MB? The service bulletin would have been required new style bolts on any gasket replacement.
Very strange, but those pesky parts departments are a challenge. It depends on what they have in stock, level of knowledge, and if they even care. It really sucks if they handed out the old style. Our parts dept., (marine), is an adventure every day. I worked at a shop with a brake pad recall and we did every one we came across. However, the replacement pads we were using from the parts dept. were the ones that were recalled! This silliness didn't stop until there was a parts recall issued! Then, we cleared the shelves, got the correct pads, and then did all the same vehicles all over again. Really stupid.
I would agree...but...could you even buy the old style headbolts after 2011 from MB? The service bulletin would have been required new style bolts on any gasket replacement.
3rd 2011 E63 "unaffected" affected application with NOS bolts I've seen. FYI, have seen updated head bolt failure. Strong suggestion on H13 studs so history doesn't repeat itself. BTW, engine serial number can be confirmed below the dip stick, link below for reference.
Back 2 head bolts are out. Less sticky but one still has the goop on it. And it was next to the cylinder with the worst performance on the leak down test, so maybe that gasket was starting to fail too?
also bank 1 bolts (the side with coolant in #2) seem REAL tight compared to bank 2.
I am now convinced this engine has been molested…and by an unskilled mechanic.
12 C63BS Magno Alanite Grey, 25 X5 Msport, 08 BMW E93, Ducati Hyper 698
I will say I saw old headbolts still for sale on Ebay like 5 years ago, so the old head bolts were pretty available for years after Mercedes stopped using them and I would suspect they were used lots of times not to fix failed headbolts as all the cars were still pretty new but if for any reason a head was off and they used them before it was common knowledge that they were a failure point and or they just had them. I also don't actually know if Mercedes put a stop sale on them or if dealers just kept selling stock until depleted.
You are probably right. Although they definitely didn’t take the passenger side off with a stripped out guide pin. My theory is that they had a head gasket issue, realized they couldn’t get the head off and just over torqued the new head bolts and prayed.
btw, the stuff all over the bolts was the ones that pass through the coolant.
Many thanks, the heads are cleaned up and back on I’ve never been more happy to own a few quality digital torque wrenches.
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Well, the head gasket failed again and then I started digging around the block and found that 3 cylinders had been very poorly lined and one was leaking coolant into the cylinder. I had to scrap the engine and I found a low mileage one out of canda. I do not know the bolt size from memory. I can check the garage tomorrow.
Well, the head gasket failed again and then I started digging around the block and found that 3 cylinders had been very poorly lined and one was leaking coolant into the cylinder. I had to scrap the engine and I found a low mileage one out of canda. I do not know the bolt size from memory. I can check the garage tomorrow.
Damn, that sucks. What do you mean by poorly lined? The plasma coating?
In principle, sure. But in practice where they don’t change the rings, properly deck the liner to the block, etc, it is just the cheapest, least reliable way to repair an m156 cylinder wall.
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