Critter

statepkt- if your issue turns out to be a broken bolt, could you take some pictures of the offending bolt and a few others out of the engine and post them, Also the placement of the bolt in the engine, ie cyl 5 top left,
Thanks in Advance

statepkt

^Definitely my plan. Will be taking lots of pictures and if the head bolts are the issue.....trust me I will get those in my possession

^^You think 2 owners at 57xxx miles is excessive and indicates a problem??? Wow, you must be trolling.

statepkt

Its official. Mercedes Indy shop diagnosed it with a broken head bolt (between cylinders 6 and 7). Bolt head broke off and got stuck in the recessed bolt cylinder (thank goodness it wasn't flying around).

Coolant was leaking into the exhaust and oil pan. Apparently I had about 1 gallon of coolant sitting in the oil pan when they took it in. Luckily I stopped driving it about 2 weeks ago after I noticed the "milky oil".

Next steps: Convince eBay policy that to cover the issue. Replace head bolts.........

Jon2007E63P30

Sorry this happened. 122k and I have the intake manifold leak. Look for a DIY in the future.

statepkt

Good news....turns out eBay will cover the repair (new head bolts/tappets/gaskets.....) ~4k

Should be getting her back sometime mid next week.....FINALLY

novae500

Good to see that Ebay kept up with its words!!!! Well at least keep fingers crossed when the invoice is paid by Ebay.

FromM3toAMG

Wow, how did you get eBay to cover it? Either way congrats!

typhoon43

I cannot believe Ebay is covering it, but CONGRATULATIONS man. That's awesome.

statepkt

Shop owner called eBay to give them his opinion. Documented everything (coolant purchases, Bill of Sale, Auction description....)

Just glad it is being covered without too much hassle. However I am looking forward to getting her back after over 3 weeks.

statepkt

Took a look at the head bolts today at the shop while they are finishing up my car.....

About 2/3 of the bolts absolutely look fine. NO sign of corrosion at all anywhere. 1/3 of the bolts look like they are about to snap at the head. The corrosion there is already causing rust flakes to fall off the bolt.

The bolt that actually had its head snap off, you can clearly see the rust seeping into the bolt (inner is lighter, outer ring has a dark rust coloring).

When the car is done I will have the bolts in my possession and I believe some of the guys on the forum are looking to do a metallurgy test on them. To me it almost looks like there was a bad batch of bolts mixed in with good ones. Don't see why 2/3 of them are near perfect sitting in the near to same conditions are the 1/3.

bhamg

Fantastic outcome, congrats!! eBay covering the repair...shocking.

DuaneC63

The following M156 engine parts are factory defective up through mid MY2011 which MBZ refuses to do a recall on. Head bolts, lifters, and intake manifold bolts. If you catch it out of warranty before hydro lock, it's about 5k to fix. If the motor hydro-locks it will destroy itself, $40k+ for a new motor.

motoman

Duane, How are the parts defective. You seem cavalier about it. Perhaps you are not surprised after the string of thoroghbreds you have (had). motoman

motoman

Good stuff. Thanks for the detail on the corrosion. Got PICS? Amazed and pleased for you if ebay comes through. Also please detail the dynamics that allow ebay to compensate. Get as many failed and whole headbolts as you can. motoman

DuaneC63

Motorman I am far from cavalier, as I have first had experience and knowledge of the M156 defects. My motor was retrofitted two years ago. MBZ has issued a tech bulleting to deal with these problems. All three part I mentioned have been redesigned.
The head bolts are a torque to yield design only to be used once. They corrode at the tops breaking off causing the head gasket to leak. Caught in time, the problem can be fixed, for about $5k dealer pricing. However if you don't catch it in time and the motor hydro-locks, its time for a new motor, about $40k. The intake manifold bolts are also torque to yield and suffer from a stretching issue causing an intake manifold leak. The design of the original M156 lifters did not allow sufficient hydraulic compression to occur fast enough causing premature wear on the take up ramps of the cam shaft lobes.These were replaced by lifters from the SLS63. Please see the sticky on the top of the C63 section to view pictures of the failed and redesigned head bolts. I notice you do have 6.3 motor. Hopefully you will not suffer the fate of many 6.3 owners or have an extended warranty. However when it comes time to sell your vehicle, unless you trade it in to a dealer or a neophyte unfamiliar with these issues, you may take a hit on your value.

Baronet1

As of when were the defective parts redesigned? MY2011? So later build 2011 6.3s and forward?

I have been itching to possibly to get into a C63. I was looking at the 2010s, but it might be wise to wait a bit longer and get 2012 or even 2013 after reading this thread.

motoman

Duane63, Perhaps resigned would have been a better adjective. Thanks for the info. What damage is caused by the leaking intake manifold bolts ? Seems like some early warning would occur there via CEL?

Let me repeat what you said about MB. Known bad parts (but no recall). So they wait hoping the failures occur after warranty or on added warranty. Great company to do business with. I will tear apart my C63 at first hint.

Why would anyone look at the CLA with 30 lbs of boost. I can only imagine what is in store for those unfortunate owners. A little more boost and you're at Indy. Regards motoman

statepkt

Got the car back finally. Ironically now I have to deal with the other common problem: Fuel Sender Leak OR worse the cracked gas tank. Should be fun.......

Pics of the bolts






Car itself

motoman

statpkt, Thanks for the great pics. A while back a thread on "head bolt research" summarized evidence submitted by owners. Your pictures seem to point toward corrosion again , originating at the head side as most of the the intact bolts look relatively normal at the block threads.

The prior thread suggested "crevice corrosion." If that is the cause , upgraded bolts will not necessarily escape this mechanism. I am strictly a read and report scribe, but if the moisture is being trapped under the bolt heads the only thing I recall that could reduce the likelihood of crevice corrosion was reduced tensile strength. This is counter intuitive so I asked if anyone had seen reduced torque/yield- turn on the new headbolts. No answers yet.

Bogeyman still at the window ? Hope not.

PS this thread should be stuffed into the main sticky.

motoman

If you can, note carefully the position of each removed bolt.

statepkt

What bothers me is that some of the bolts look perfect while others look like rusted junk you find in the junkyard. All the bolts are going through the water jack and exposed to coolant (and I would expect the heating and cooling ranges are similar between the positions).

Does anyone know if the revised bolts have had a metal change? I have read everywhere but no one seems to know. The design change itself as you stated will not resolve the corrosion problem. The only good thing is no reported failures on engines with the new head bolt (whether that is due to low mileage/time or actual design improvement who knows)

Yeah I wish I had the bolt positions, but the shop didn't keep track them. The only thing I know is my bolt broke between cylinders 6-7

Critter

Could you explain how the coolant is kept out of the head if the bolts are subject to coolant immersion. I am having difficulty wondering what the sealing factor is between the head bolt washer surface and the actual aluminum head. Also the threads although very long on the shaft seem to have no sealant on them? Are the bolts actually surrounded in coolant? What am I not seeing or understanding? Glad you have a car again.
Are we looking at electrolysis at work?
Were the bolts that look the worst closer to the exhaust manifolds?

motoman

statpkt, Restating here what was in the earlier thread...Engine design "apparently" relies on thread sealant in the block threads to keep coolant out of the bolt/ head area. One Jaguar site stated that the bolt heads themselves were a final barrier (my words) to coolant into the valve train area. And merc63 told us of ?sealant? used by his race shop under the bolt heads. Of course? the coolant loss phenom on C63 is due to coolant entering the combustion chamber via the relaxed or blown head gasket , probably after the bolt head is snapped off.

Even though I say "crevice corrosion" I keep vascillating. Your bolts look like coolant "could" have gone up the whole shafts, but something triggered the runaway corrosion on some? To my knowledge proper coolant is not affected by temp gradients, and I do not know how/if fresh coolant separates so that water alone is somehow at the top of those corroded headbolts.

I ramble so some expert will chime in, hopefully. All this is moot except for curiosity as these cars age and MB corporate shrugs the problem off as routine maintenance. ( Yeah, my lowly , running 26 year old GM iron block has never been apart) Neither has the SR20 in the Nissan.

DuaneC63

Baronet.
The sticky of the MBZ service bulletin indicates the engine serial numbers impacted. Some 2011 fall into this range. The only way to know for sure is check the engine serial number. The 2012 and later do have the wet clutch pack instead of a torque converter. However these are prone to overheating with heavy usage. At the AMG driving academy they put blower fans under the C63's and let the engine idle after they come in from the track. Nothing an extra large tranny cooler won't fix.

Critter

Would it be possible to have the owners that had bolt failure to remark if their coolant was ever changed and if it was did the change include tap water or distilled. Also was a good ratio of anti freeze and tap water or distilled water used. Does anyone just use water in their Benz, tap or distilled, just asking.
Still thinking this has something to do with electrolysis with the dissimilar metals of the block and the head bolt along with acidic coolant.
Comments !