M156 head bolt problems
Ive talked to Sweden largest MB dealer and they have just had one car with this issue! Of a few hundred sold cars in affected years.
Had a talk with Kleemann in Danmark as well and they have had a few but not something that was common and told me not to worry.
So even for us with 2008-2009-2010 cars I dont think we should be TO worried. I can happend but it doesnt have to.
Hopefully ;-)
If there's indeed such a figure out there, it shouldn't surprise us that it may not be any higher than other porential component issues in Mercedes cars, or any other manufacturers for that matter.
CHEERS FROM FLORIDA!


Regards,
Joe
Questions 1) Am I even eligible for MB extended warranty? I am at like 50300 miles and slightly under 4 years. 2) If MB is no, are there any aftermarket warranties that are legitimate and actually pay out when problems arise? 3) Is there a safe mileage to be in with these reported engine issues?
(1) Any instances known of "new" OEM headbolt failure?
(2) Any instances of ARP stud failure?
(3) I can't really tell if all/some only/any of the headbolts is "sunk" in a counter bore. If not all sunk, pattern of broken ones? Important , please.
(4)One picture shows the old headbolt with galvanize coating-true?
The newer bolt looks dark like ?oxide" coat or oil coat?
(5) Merc, more detail on Weistec 500 deg silicone sealer , please.
(6) Any known patterns of owner failures such as (a)short commutes (b)long commutes (c) mixed ? (d) region?
yes , but trying to understand.
The Best of Mercedes & AMG
#24 tri star tech...saw three things significant to me (1) a clear statement of why the later oem bolt may be stronger at the top (2) rust on the shank of the old oem bolt. This is the first time I have seen rust covering anything but the very top of the bolt. Suggesting the coolant past the block threads indeed may be the culprit.(3) "slow coolant leak" suggests I will go ahead with the oil analysis kit i'm holding.
#32 bhamg quoting morgan...the Aussie shop sent out the engine to pressure test by (a) bolting on head with new gasket and OLD HEAD BOLTS, and the coolant came "up thru" the head bolts. Old TTY bolts cannot clamp properly...I wish morgan could tell us exactly where the coolant came out- around the headbolt flanges? Were the headbolts already cracking and tilted? (Please know this is not a criticism of morgan.
His thread has been very good).
found on mrtazzy.com pg id 59...describing the old oem bolts..."the tool interfacing is cut so deep that the head bolt develops fishers (sic) at the base of the bolt weakening it..." So with this we hear that the ?cold heading? operation was defective (as well as the head being too thin)
But fissures sound like cracks, not tooling marks . Just more info...
#32 bhamg quoting morgan...the Aussie shop sent out the engine to pressure test by (a) bolting on head with new gasket and OLD HEAD BOLTS, and the coolant came "up thru" the head bolts. Old TTY bolts cannot clamp properly...I wish morgan could tell us exactly where the coolant came out- around the headbolt flanges? Were the headbolts already cracking and tilted? (Please know this is not a criticism of morgan.
His thread has been very good).
I'm waiting on a reply from my MB dealer if they can cover in replacing the head bolts as I've notified them late last week on this issue. Else, gonna have to ask for a quotation from them and gonna compare it to Weistec's items. If it makes sense, I'd might as well get items from Weistec Engineering and get the dealer to do the works for me.
How reliable is this car after they warranty the head studs? Has anyone had repeat problems?
Funny thing was I read this post before I went to the dealer and immediately knew what happened when the coolant light came on and it went in to limp mode.
Please post the mileage when you get a chance...thanks and good luck with this car. Getting it fixed like this before you take delivery could be a very good thing.
Have had my 2009 for a few months and the more I read about this the more Im concerned if I did the correct choise to sell my M3 and get the C63.
Love the C63 but since we dont have any extended warranty in Sweden I have to trust my insurance to cover this issue if it happens.
And they can be a pain to deal with. :-(.
Its a bit weird that pretty no one of the MB dealers here In Sweden seems to know about this head bolt issue?!?
How reliable is this car after they warranty the head studs? Has anyone had repeat problems?
Funny thing was I read this post before I went to the dealer and immediately knew what happened when the coolant light came on and it went in to limp mode.
How reliable is this car after they warranty the head studs? Has anyone had repeat problems?
Funny thing was I read this post before I went to the dealer and immediately knew what happened when the coolant light came on and it went in to limp mode.
Yamdan I drove a 2011 M3 6MT back to back with an 09 AMG without Performance package or LSD and they arent even in the same ballpark. Was so disappointed coming from the car I am trading in (a COBB Stage 2+ Tuned 2008 BMW 135i FBO car with a killer suspension setup).
Thanks everyone for the quick replies, talked to the dealership last night and the parts come in Monday or Tuesday and should be able to pick up the car a week from today!





