DuaneC63

There is a sticky in the C63 section with the range of engines serial numbers with the old head bolt design. The actual service bulletins are not available to the public. They pressurize the cooling system overnight to confirm the problem.

DuaneC63

Scroll down. Someone got dealer quoted $4,600. It more that just replacing head bolts. Their entire top half of the engine has to come off and the cams removed from the head to access all the head bolts. New lifters are also installed

Mbm6f

Trust me - I don't need to be told how asinine this is. I'm going to call back and make sure he understood me because that has to be a mistake. Literally just replacing the head bolts.

Valvestud

Here is the TSB:

bob2011

Jeeze, I was seriously considering a 08/09 c63, but after reading this is might have to reconsider. Is it 100 percent certain that I will encounter the headbolt issue if I buy a c63?

Valvestud

There is no absolute regarding this issue. It appears to be limited to a small number, but there is no data to support when or how many. So you either buy a late 2011 or newer, or keep and extended warranty, or roll the dice and repair on your own if it occurs.

Ben Knocks

Any advice welcome, my cl63 6.2 2007 160k miles owned from new.

Merc has just called to say a left bank head bolt has snapped, i have been in and out of the garage now for 5 months as I knew something was wrong and then the coolant started dropping.

i'm gutted my car has been faultless now for nearly 9 years, so good i have bought and sold various other cars and always kept the CL .

They said they will look for a contribution but i think the day has come to let her go .

computertom

What's the resale on that with that level of mileage? Is it worth it to fix, cause it's not going to be worth much with a down engine...

All that said, how bad the damage is, might be the key. Is $4K worth it to have this great vehicle back in business? Unless things got really ugly, you could be looking at that level at an indy.

That said, at 160K miles and 9ish years, this old beast might not owe you a thing.

Ben Knocks

The trade in value has always been very disappointing on the CL, approx £12k with engine running, so maybe half that now.
Merc need to remove the chain today to further inspect, but the head bolt has sheared.
It has become a sentimental thing now, Just hope it is not mega bucks, at this stage in her life it's the knock on effect, and what will go wrong next.
Thanks

builthatch

yeah, it depends on the extent of the damage but my guess is that you will be in the best position if you get it fixed then list it for sale, vs. the alternative.

DuaneC63

They will have to pull the cams and heads off. The lifters will need to be replaced and check the cams for wear. As long as its apart you may consider a vavle job depending on cost. That way when you sell it (or keep it) the entire top half of the engine is new.

Ben Knocks

Called today to say two bolts and two banks affected.
MB not contributing to the cost. Any advice on debating this with Mb, seems to be a long standing dispute with the head bolts as a defective part that has been replaced under warranty in the past for other customers.
I not happy with this response, the car was bought new and always serviced at MB.
Looking at £4k to repair.

Celicasaur

Surely that is solid ground to stake a claim for more support from MB. I'd get in touch with their head office personally and go inn on the fact that you're the only owner and it's always been maintained as per their specifications etc

Ben Knocks

They have come back with something about a customer matrix and referred it down to head office uk, so lets see, I've spent 2k replacing pumps and diagnostics at this stage, and it was the heads bolt all along !... thanks

Merc63

Sounds like you have retards working there, find a better shop. Anytime coolant is lost on a m156 headbolts are my top 3.

JordanSpaceJam

What are the other two issues?

My low coolant level light comes on after the car has been parked outside at the office all day. Its gone though by the time I exit the parking lot. Is it affected by low temperatures? Been pretty cold up here.

Jasonoff

Could be thermal expansion of the coolant turning the indicator off if it's right at edge of the on point when cold.

Merc63

The sensor is really sensitive. Top the coolant up some. Test the oil for coolant. Could also be leaking coolant.

trustn0187

I picked up a 2009 with 49k last month. I contacted a local shop > http://imamotorwerke.com/ that I found off of Weistec's website.

The owner said it would be $1000 for the bolts, and $900 in labor to swap the bolts out.

Doesn't this seem too cheap? Should I ask for a quote to also replace the lifters while they're in there? Anything else I should do.

I don't have any symptoms but reading these forums scares me

Ben Knocks

Just got my car back, the minute i got home the engine light came on, so i went back and they done something with the cams. Sounds better than before !!!
It was £3300inc vat.
No help from Merc uk or Germany after various emails and phone calls, the dealer offered £300 on the labour, so i think I will get an indy to service in the future.
It's a great car, the best i have owed to date, I am hoping to retire her into the garage in the next few months.
I'm going to buy a Jag F type R for the crack and wait for the GT to bottom out.
Thanks for your help guys and best for luck !!!

hyunman

Have you ever followed up with the dealer on this? Based on what others are saying, it's looking like about $5000 for the dealer to do a preventative fix - is that about right?

I'm in the affected range and out of warranty. Really love this car - just don't want to keep worrying.

lmterre

Hi all,

I thought i'd share my post-repair experience and a copy of the bill.

Firstly, this entire ordeal was really a pain, but i still love the car.

I went with dealer-repair route with no help other than parts @ wholesale price and discount labor fee of $300.

I guess it was somewhat of a win.

Anyway. Got the repair finished in about a week. I figure they had one guy doing all the work.


Came back running smooth and strong. No hiccups at all.

A week after driving I noticed oil drops in the garage. I didn't have an oil leak before. Took it back to dealer. They first said I need to replace my oil pan because it was cracked and would $900. I said "it was not leaking before, and I haven't done anything abnormal to make it 'crack'. It must have been when they were putting drain plug back in." After my logical argument with tech, they agreed to perform the repair at no charge. Fixed the issue. no more leaks.

Anyway, now I'm about 1000 miles in on the engine and it runs like a champ. Still love the car.I attached the invoice for everyone's benefit. Please don't tell me i should have done X or Y because it's already been done, and I don't need any more anxiety about this thing. The work is warrantied for a year or 12k miles. I'm taking it back and holding them to it if anything goes wrong.

Hope this information helps anyone experiencing the same issue.

I would strongly urge and buyers of the M157 to get the head bolts changed out as a preemptive tactic to avoid this issue! i would imagine this would be $2000 vs a possible minimum $4600 or completely blown engine depending on when you catch the issue!

realjones88

Thanks for sharing your story. I think you mean the M156 engine though

The M157 is the 5.5L twin turbo V8.

I have heard of places changing out the bolts one at a time, which must save some steps somewhere. It would be interesting to see the difference in cost of repair (although if it's $1700 in parts alone it can't be that big).

I do also think is a low percentage issue....we have seen just as many posts from members with 08-10 cars with over 100K miles and original headbolts. Sorry you were one of the unlucky ones.

Euler

I had an indy shop quote me $1000 labor for one-at-a-time replacement if I supplied the parts. Bolts from the dealer are $15 each x 20. So, sounds about right to me.

I think I'll still give it a go myself though. My 2008 has 51K miles and so far no issues. It's my DD and I don't push it hard. It's hard to find a decent cop free stretch of road around Atlanta.

BigMike62

Did the M156 head bolt issue span across all models or just the C63? Wondering if it affected the CLK63. Seems like it would but haven't seen any posts about it. Thanks.