Motoman, of the 3 German sources is there any one source that has multiple failures. We had talked before about AMG designers obviously did not buy all the headbolts at one time and we see more failures in the C class for some reason but recently a few of the E have rose up, was going to say popped up but!!!
I run Water wetter in all cars do you believe this will reduce the formation of "micro bubbles" with the coolant system?

 

The failure is always the head coming off. The original bolts, with inset pattern, are the problem. The new bolts, with external pattern, are the solution. It has nothing to do with corrosion. If it did, the breaks wouldn't be at the head where the head gasket protects the metal. The head was not redesigned -- the bolts were.

The chemistry of our coolant is pretty complicated. I wouldn't add anything.

 

It's more common on the C's since there is alot more C-63's made, not to mention because of this more are actually driven. Non of mine had failed yet, this was more of a preventative maint. no cotton gloves used for the install, but they got fresh latex gloves

lol you think germans will ever admit they did something wrong? The new design isnt because the old ones are bad or fail, it's because they improved them AMG engineers are too busy with the new motors to worry about problems cars out of warranty have.

 

We have so far only seen the "big world" defects visible to naked eye. There are several "small world" failure mechanisms of interest. IMO 1. stress corrosion 2. tensile strength (hardness) 3. crevice corrosion (remote). Takes high paid guys on high priced equipment -scanning electron microscope (SEM) to analyze. Seems MB addressed 2. above with the newer bolt by dropping the hardness to M 9.8 from M 10.9.

I spent a year surveying test labs. Most don't like private parties, but several will do the work . Prices $1700 low, $ 2400 typical. Best deal offshore Mumbai India at 1/3 US prices. Never brought this up since I could barely get ahold of even several sample bolts. Knowing how hard a group buy is, such a group ante seems difficult. Will supply sources if asked.

We never did establish any pattern of headbolt failures by vendor , I believe. I am not familiar with water wetter.

Head gaskets cannot protect the the headbolts which pass thru along with the coolant which surrounds the shoulder and flange.

 

WaterWetter®

• Unique agent for cooling systems that doubles the wetting ability of water
• Rust and corrosion protection allows for use of straight water in racing or reduced antifreeze levels in warm climates
• Improves heat transfer and reduces cylinder head temperature
• May allow more spark advance for increase power and efficiency
• Use one bottle for most passenger cars and light trucks, treats 3 to 5 gallons or 13.2 to 15.9 liters. Vehicles with larger cooling systems should use two bottles. Small cooling systems should use 1oz (3 to 4 capfuls) per quart
• Compatible with new or used antifreeze (including DEX-COOLTM and long-life versions) to improve the heat transfer of ethylene and propylene glycol systems
• Satisfies ASTM D2570 and ASTM D1384 corrosion tests for glycol-based antifreezes

 

let's get some bolts tested, that will tell us how much the strength has been reduced (for what ever reason)
would be nice to have samples from various years and mileage.

you start collecting data like this and MB USA will take your arguement more seriously

I use the Water Wetter, basically a surfacant, better contact between coolant and metal, ie, better thermal transfer, or so they claim

 

Have there been any reports of the new bolts failing? I haven't heard of one case. If you guys believe the problem is with the bolts' environment and not their design it's only a matter of time before new engines start failing.

 

environment may be a factor in the time to failure but the root cause is the bolt design (I think everyone agrees on this?)
MB has tacitly acknowledged that by changing the bolt design

 

Thanks for the pictures, they are great for people like me who don't know what the parts look like. You mention the cam adjusters were loose. Did you know this before you opened the engine or was there something that gave signs of the problem? Also how many hours do you think a MB garage would typically quote for opening the engine for inspection. (sorry for so many questions
thx

 

Didn't realize this very informative thread hadn't made it into the sticky so in it goes.

 

Loose as in not compressed - compare those 2 pictures. - sorry for not clarifying that. see the 2 sets of teeth- one is slightly spring loaded so the gears mesh nicely. There isn't any problem with them at all. Well mb labor time gives about 13hrs for this job on the c63 which is a total sham. I'll have to check and see what the labor time is in other models. Typically the cheaper the car the less labor time is allowed even if the procedure is the same or even easier. If someone does this in that time they are going way to fast. Keep in mind it also included 2 oil and filter changes after the repair is made. Most shops charge 35%-50% or more over the warranty time. Id say 20hrs is a fair time for this repair. Where the job isnt getting rushed or short-cutted and the owner isnt getting hosed. Most people probably wont take the time to extensively clean everything either and mb doesnt pay for that either. If the engine is higher mileage i'd also recommend going ahead and replacing the valve stem seals and possible lapping in the valves if they aren't sealing well. I didnt bother because this motor is still pretty low mileage and only a 2010 car. furthermore, if you have headers it will add to the cost of the repair as they will have to be removed separately from the cylinder head for removal, unless the whole engine is removed - which is not included in the repair either.

 

thank you, im flattered

 

wow... i must have missed this thread... this would have been pretty cool to see since you're in dallas...

how's the car running?

 

car is running great.

 

I realize this thread is from some time ago, but I'm in the midst of doing weistec head studs on my 2010 C63 and I'm trying to get as much information as possible so this is the only time I have to do this job. My question to anyone who has the answer is, what type of head gasket do these engines use? Is it an MLS gasket or composite? The reason I ask is, I already have coolant leaking into one cylinder, its what prompted the repair. It's not excessive, however, the top of the cylinder is wet, the spark plug ground strap has a thin film of white material caked to it, so it's been leaking for at least a brief period of time. I'm wondering if the head gasket is a MLS design, if it's possible to remove the head bolts one at a time and replace them with the studs if doing so will seal the leak and thus, prevent me from having to remove the head? I realize that with older composite gaskets, once they leaked fluid, they were saturated and therefore, would never again create a seal. However, I believe an MLS head gasket is capable of re-establishing a seal once the pressure is reapplied. It's obvious that I have a stretched or broken bolt in the area of the cylinder that's leaking, and that's what's causing the leak. My concern is, I really do not want to remove the head, but I want to do this job twice even less. So, if there's a chance I can get away with doing one bolt at a time, I'd like to get away with it. If those of you out there who have experience with MLS gaskets, of which I have none, can weigh in on the integrity of the seal after a leak has developed, I would greatly appreciate it. Thanks gents.

 

If the gasket has been compromised at all, head(s) off and replace. Sorry.

 

@BLKROKT - I mean no disrespect with what I'm about to say, so please do not take offense; I am merely trying to collect information in an effort to make an educated decision. Having said that; what evidence do you have to substantiate your claim? You responded with the exact same reply in the head bolt DIY discussion where I asked the same question. I certainly appreciate your response and opinion, but forgive me if I don't blindly trust what you say without some information to back up your statement? The reason I'm even asking this question is I have absolutely no experience with MLS gaskets, but I have heard they are very resilient and have even heard of people reusing them on engines that have already been run. I have read that as long as the coating on the top and bottom of the gasket is not disturbed, an MLS gasket can actually be used more than once without issue. Again, I don't know because I have no experience with MLS gaskets. I am looking for people who do. If the m156 was manufactured with a composite gasket, I wouldn't even be asking this question; I know full well that if a composite gasket is compromised, its useless and needs to be discarded, end of discussion. But, since I believe that due to the higher compression ratio these engines develop, AMG used a multi-layer steel gasket and I have heard/read many different things about these gaskets. Please be more specific about what makes you say that if there is a leak of any sort; even if that leak is due to a broken fastener, not necessarily a failure in the gasket itself, that a new one has to be used and cannot just be re-torqued. Thanks in advance.

 

The HG appears to be is metal according to any online part catalog.

Looks like it's multi-layer metal as well on the Wesitec site. I would guess once it has been soaked in coolant it could compromise the mating surfaces.

 

Why not try and see worse case scenario your back taking the heads off...

 

Or grenade your motor via hydro lock...

 

This is exactly what I'm trying to avoid. Maybe I'm beating a dead horse here and I should just make the effort to remove the head and replace the gasket, but the further I get down into the engine, the more concerned I am that something may not go back together properly, I might break something, more gaskets and seals are required, etc. Again, if I can get away with it, I want to avoid removing the head if at all possible. I suppose that on the bank with the issue, I could remove all the ******* bolts, replace them with the studs, fill the cooling system, pressurize the system and see what happens. If that cylinder fills with coolant, I know I'm taking the head off, but I'm 80% of the way there. If it stays dry, then I can take a calculated risk that the gasket will seal once everything is up to operating temperature and properly expanded. Thoughts anyone? Anyone tried this?

 

I'd be concerned with trapping coolant in the gasket preventing proper head to block mating.

 

If it hasn't hydro locked already replacing broken studs with new ones and firing it up isn't going to hydro lock it...
The right way to do it is definitely replace them properly or your never going to trust it in the future even if it does work...

 

We both agree you can not compress water, coolant in this case right?

If he has a coolant bubble trapped between the HG preventing proper mating. What's to stop it from creating a water path channel? You bet your *** hydro locking the motor is on the table of possibilities...

 

It's worth a try. If a metal gasket, tightening down the studs will push out any liquid as you clamp it down. I'd bet it will be fine. There is an enormous amount of clamping force with those studs torqued.

I've seen Harley's with leaking metal head gaskets, torqued back down and be absolutely fine.

There's no way your going to hydro lock the engine unless that gasket blows apart.