6_Myles

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:
Let me know your thoughts on what I'm dealing with.

As always, appreciate the help!

JimboE63

Are the cams stamped AMG? Is it possible someone worked on the heads and used NOS head bolts in the reassembly?

6_Myles

yes they are

Jasonoff

That engine has been worked on. You're over 900 engines built after they stopped using the old bolt design.

6_Myles

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.

AMGSPY

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.

Jasonoff

Indy shop could have had them on hand.

Panzerbiscuit

Is it possible that they are "used"? Like an Indy shop or dealership pulled them out of an engine and chucked them back on the shelf?

N I L

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.

VRP H-13 Head Studs for the M156 AMG Engine | VRP Speed

BLKROKT

There have been at least two other instances of cars past the engine number cutoff with old head bolts. Documented here. Just bad luck.

6_Myles

To further complicate the situation, someone has def tried or was successful to get into the engine. The lower guide pin on bank 1 was stripped out.

for future reference there is enough meat to drill/tap it out to a m8 and removed.

almost have all the head bolts out on bank 1. Two do not want come out of the head, like they have goop on them. Will update later.

6_Myles

Head bolts out. Top of picture is top of head. Right of the picture is the front of the engine.

#2&5 on the top had some weird goop on them. I presume coolant and/or oil?

6_Myles

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.

Picture orientation is the same as above

6_Myles

Heads are off. Verified it was the factory number, thanks for that video.

Accidental L8 apex

Most plausible story IMO is an indy tried to repair it and had or got old bolts to fix it and here you are.

Sucks, but you'll obviously get it fixed right. 👍

roadkillrob

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.

6_Myles

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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Radfox02

How is everything holding up?

Do you happen to know the thread size of the head bolts?

6_Myles

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.

Radfox02

Damn, that sucks. What do you mean by poorly lined? The plasma coating?

6_Myles

No, they bored out the cylinder and put in a steel liner. It’s a hack job of a repair to get it running and out the door.

Radfox02

Wow! Now that your familiar with this, is the fact that it is sleeved discernable in your photograph of the block without the heads?

6_Myles

yes, now that I know what to look for. Cylinders #2, 5, & 6.

deadlyvt

There's nothing wrong with steel liners... infact you can get ones that are a lot stronger than the factory bores

6_Myles

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.