E63AMGEdm

Hey everyone, Sorry I know this topic is getting annoying! I am curious if any one has had or has heard of anyone that had issues with replacing the head bolts with the one at a time procedure. Still debating what method would be the best for myself it makes sense that there is still a lot of pressure with 9 bolts and the more a read forums the more tempting it gets!

(It is an e-class forum will not let me submit in the right catagory)

AMG3.2

https://mbworld.org/forums/c63-amg-w...adventure.html

jptaylor

https://mbworld.org/forums/c63-amg-w...ust-means.html

hachiroku

yeah...your engine didn't explode

jptaylor

Not sure what that means.....

hachiroku

the comment was...because a few of us...even in this thread have done the 1 bolt at a time method. if not done...you may have a random engine failure like one member just did in the W211 forum.

its crap shoot. if you want an M156 its highly recommended that head bolts be done if you don't have an engine with the updated bolts already.

jptaylor

Still lost by your comment....OP was asking about the 1 at a time method and the link I posted was where I did my own 1 at a time, 40k miles ago....the only question is the integrity of the head gaskets...when you get inside the head to do it you will be able to tell if coolant is coming up past the bolt head, if it is then you are somewhat safe that the head gaskets will live as the pressure found a vent other than destroying the gasket....and since I also don't understand the comment about random failure elsewhere I will say this, if you have the affected bolts and don't change them it is NOT a random event when they fail, it was inevitable, they are GOING to fail.

iownedu

If it isn't broke, don't fix it.

This issue is so overblown it's ridiculous. I've owned 3 pre-2010 m156 powered cars with mods. Not one issue.

jptaylor

Overblown? Consider this, MB revised the bolts, period.....that alone should be more than enough info to realize there IS a problem. What kind of mileage on your 3 pre-2010 M156 engines? Everyone here that has had the failure just made it up... Where is Jim????? BLKROKT, handle this please......

iownedu

Handle what? Can't fend for yourself or what?

One had 80k, one 115k, and now one at 91k and counting. Headers, tunes, you name it other than superchargers.
Manufacturers revise things constantly throughout the life cycle of an engine, nothing abnormal.

Again, exaggerated issue.

jptaylor

Wow, you're a spunky little ***** aren't you? Here's the thing, yes, mfg change things l the time, however, they don't change the pressure holding components in a 60 million dollar engine design if there is no issue with it...also, why exactly do you think most times(at least in the past) when head bolts went the dealers and MB were usually willing to at least foot half the bill? It was a **** poor design to begin with, removing material from the inner structure of a fastener, especially one which is tasked with one of the harshest loads the engine will ever see. Couple in the electrolysis factor creating corrosion, big chunk of metal with constant high amperage current flowing through it filled with moving coolant, and it is not an if but when. I have been here a while, other boards as well, and I honestly think you are the first moron I have seen hit this topic with the "if it ain't broke don't fix it" comment. I expect this type comment on a BMW forum but come on guy, you're better than that.....

iownedu

Moron huh? Grow up.

jptaylor

There is an old adage how it is far better to remain silent and let everyone think you're an idiot than to open your mouth and prove them right....People depend on relatively sound advice on these boards in order to offset their lack of specific knowledge as it relates to their vehicles.....they could turn a $500 job into a $5000 job by taking your short sighted comment to heart and not acting prior to catastrophe....instead of the if it ain't broke crap when it comes to the headbolts in M156s the quote that SHOULD be used is an ounce of prevention is worth a pound of cure.....I'm done with it

Mag1c Carp3t

jptaylor

LOVE IT!!!!!!!

rnorthen

I was planning to have mine replaced one at a time by MB before my warranty ran out. The first one they pulled came out in pieces, so they did the whole job under warranty. $13k was the total, thankfully fully covered under warranty. New headbolts, new buckets, etc. Only 30k miles and only mod was a tune. It's a poorly designed part that will fail, replace them.

G_Money

Are the valve buckets a problem on only PFL M156s or all of them?

jptaylor

Others may have seen different results but with 160k miles on them when I did the job they literally looked mirror polished....like brand new. The lifter faces, every bearing and every journal looked brand new, I was very, VERY impressed

AMG3.2

Mine looked great as well, but I still replaced them since I was already in there.

My cams:
Attachment 441568

My lifters:
Attachment 441569

Jasonoff

Fair play. But, fixing it when it's broken is much more costly and labour intensive than going the preventive maintenance route.

I wasted my time and money going the preventive maintenance route and discovered my bolts were nasty AF. Would they have failed any time soon? Maybe, and that was good enough to help me sleep at night.

D3-AMG

When I joined this forum at the end of 2014 while looking for my car the consensus was around a 3% failure rate. That has evolved to now saying get them done because they will fail eventually. Contrary to that, the local Benz only (non-dealer) shop I talked to was against going in there unless there was already a problem. They had done this job on a few different models with the m156 under the hood. But their general feeling was this is not a ticking time bomb. I had them replace my intake manifold due to a crack in the rubber hose feeding the back side unde the Y connector from the airboxes. I feel pretty good about them knowing what they're doing.

hachiroku

its a crap shoot...some have failed at 15-30k, some haven't failed at 181k.

replace them or not, it's your choice, but the part is a legitimately subpar part. i replaced my buckets along with my headbolts both with updated part numbers. the bolts per my friend looked brand new with ZERO corrosion, rust, or signs of weakness. the buckets looked fine, the camshafts themselves seemed to have lost some chrome plating ever so slightly. each replaced bucket didn't seem to exhibit any uneven wear.

Jasonoff

Here were mine.

Edit: Attachments weren't working properly. Full swap below, HBs are in the album.
https://drive.google.com/open?id=0B7...V9HSklQY1BUYVE

Savage-wp

You just need to look at a sectional picture of the old style headbolts to see just how badly they were designed.
The shop that tunes my car, had a 2009 C63 in for repairs as the headbolts had failed.
I had a good look at the bolts that came out. They are ****.
New design is much better.

Valvestud

We all agree the original bolt was poorly designed. But I believe the reason the failures are relatively rare, is that one or more batches had either metallurgical or post manufacturing treatment issues. This would help explain why the failures occur at different times in the life of an engine, and would also make it hard to track where the parts got used.