Valvestud

That's the understanding, yes.

Regards,

Joe

bhamg

No one has chimed in with anything definite but IIRC from a few prior discussions it could extend +/- to the 4th-6th month of 2010 production.

GrnLantern

I have a 2010 whose M156 engine is part of the affected engine group (i.e., the # is within the range).

rockdizzle

i have a 2009 c63 amg with 49000 miles with no problems yet. Am i still at risk for head bolt issue? Ive read forum and its 50/50 some people have 75000 miles with no problems. I love the car but should i get rid of it b4 im the next victim? Thanx

Merc63

No, you're over reacting.


Its not as wide spread as people think.

Of course if your engine has major problems your going to start googling and coming on MBworld right away making posts..

The big majority of people aren't having issues.

rockdizzle

thanx merc63 guessing your 63 has no issues and its tuned, how many miles?

Merc63

62,000 km on that engine and no problems.

Just picked up another one with 60,000km and its fine.

In my city, there hasn't been 1 head bolt failure recorded.

CoolBDPhenom03

I've put 20k miles on this car so far for a total of 42k. No issues so far and I can't say I've heard of this issue outside of this forum. I'm aware and alerted, but it does seem like a rare or at least a very uncommon issue.

otakki

Yes, the problem is rare. But you have to ask yourself, am I able to weather the storm. It's like a holding bomb that you don't know when it is going to go off. If you still have the warranty, it's going to be only hassles but no financial loss. As for me, I'm gonna trade it in before the factory extended warranty ends. I really hope MB will just have a recall so I can keep the car, but that's unlikely unless you take them to court.

rockdizzle

i have an extended warranty not through mercedes got my mechanic looking to see if it will cover if it does happen, cuz i want to keep car as well its a beast

DuaneC63

This seems to be the general view point. It's a $5,000 problem if you catch it in time and a new engine if you don't. Out of warranty MBZ has shown some consideration working out a cost sharing arrangement in some cases (especially if the motor goes boom). Personally I wouldn't own one out of warranty even if this wasn't an issue. Major repairs are just too expensive.

What's the difference between a spin and a crash.....the sound at the end.

Merc63

If you need to have a shop fix your car if problems arise with it, I would get a powertrain warranty that will cover the engine.

Like the one guy said, its an issue, no one knows who it will happen to. Can you afford a 20k bill? If yes, don't get warranty and risk, if no, get warranty and cover your ***, or buy a newer model with the updated headbolts.

I have a 2010, its affected.. I think the black valve covers is the sign from MB that it has the new bolts.

rockdizzle

if i tune my car am i making the chances worse?

DuaneC63

You're making the chances worse that MBZ will deny your warranty claim.

CoolBDPhenom03

That's so lame. This is a known issue and there are enough documented cases. The manufacturing quality should preclude any mods. I'm really surprised there isn't a class action suit yet.

Sincity

Though a tuned one takes it to a regular E63 and slightly beyond depending on tune.

bhamg

This is JMO, nothing more and totally unsubtantiated with any facts. Based on some conversations with a couple of people who work for M-B about the relative frequency of failure across the output range of the M156, I'd guess it increases the chances of head bolt failure...slightly to moderately. Now, is there a meaningful difference between a 2% or a 3% chance of failure (bearing in mind the latter figure is 50% greater than the former)...the answer for me is "no." A tune will raise cylinder pressures, and with potentially defective head bolts increased cylinder pressure is never a good thing. What's the pressure increase? My guess is a minimum of 10% with a tune. That's one reason why chasing the last few HP with a tune just to put up a number while not a fool's game has never made sense to me.

ZephyrAMG

I am a realistic thinking guy and this post has a ton of common sense in it. Not that the engines shouldn't be able to handle the extra HP, but with the head bolt issue, it will be exacerbate the issue...it just has to do with natural physics...

DuaneC63

Agree that a tune that pushes the limits (too much advance etc) will cause all kinds of problems including exacerbating the potential for a head bolt issue. Remember these engines were detuned by the factory for marketing reasons, not engineering reasons. It's rare to find a NA engine that gets up to or over 50HP from just a tune. The real issue with any tune is that it voids your warranty and it may not have caused the head bolt failure to begin with.

bhamg

I'll put some of this recent discussion in the sticky later but here's an interesting treatise I bookmarked some time ago. It's well worth reading about the engineering that went into the M156 motor. I recently went back to it and there's an interesting addendum (which I won't quote beyond the opening).

http://www.marcusfitzhugh.com/CLK/63.html

2012 Addendum: Time is beginning to reveal a few secrets . . . . . . . .

Early M156s have serious top end issues. Early as in through engine number #60658 (those are the last five digits of the engine number and this issue impacts all 63 engines through the early 2010 vehicles). "Issues" as in plural.

rockdizzle

oe tuning says that the factory wont be able to tell the car was tuned if you take tune out before you go to dealer? That was a great article, i called ray catena mercedes inunion and edison county about this issue and there answer was that they never hear of this issue on a amg engine n that no cars have been to either place for service of this kind. its just funny that mercedes makes an upgraded head bolt!!!

02Drunkenup

so is anybody having a bolt replacement done on their own terms? as in having the new bolts or weistec heads put in without any failure or symptoms?

I really want to get into an 08 to keep the next 4-ish years stock but this is really pushing me away to alternatives.. but I guess i can always just have it done down the road

DuaneC63

I thlnk that ACG Automotive in San Diego has done a few with weistec head studs. If you're not going to mod the car, you might as well wait to see if it fails (just make sure you are alert to the symptoms before you hydrolock the motor), then complain to MBZ who seems too be willing to work out cost sharing in some cases. Don't let them hit you with their insulting "assesment charge" if you decide not to have them do the work.

02Drunkenup

hmm... while I'm not fond of the idea of waiting to catch it at the last minute that probably is a better option than getting an aftermarket warranty and getting denied of coverage. Oh well, I guess I'll ask my indie about the issue, thanks!

CoolBDPhenom03

Neither my dealership here in WC nor the indie shops around the area had really heard of this issue before, so that is somewhat promising. I have a 3rd party extended warranty, but I'm not completely up to speed about the specifics pertaining to modifications, or if there are any.

Fingers crossed.