CigarXO

Forum -

I own a '95 C36 AMG with 140k miles. About 1 hour into a highway drive I experienced an overtemp condition with no prior warning resulting in heavy gray smoke (I think from oil burning off engine/oil pan from minor leak in lower gasket) and coolant low level indicator. After it cooled, pulled into small shop. Diagnosed as bad Thermostat (delayed replacing because cover bolts corroded), coolant cap(replaced). Mechanic also believes main fan clutch faulty as he could stop it with his hand? Limped it home with heater running to aid in cooling. Rough idle, running hot. No codes.

Brought vehicle to my regular mechanic who replaced Thermostat, cleaned up cover, replaced bolts. No other concerns identified. Left with smooth ride.

Next drive started smoothly, but led to rough idle(P0301 code), hot condition (100degrees) and Check Engine lamp.

Any ideas? Catalytic, Fan, ...
While my mechanic is cheaper than a Stealer, I can't plunge into hit/miss diagnosis. Car is well maintained, serviced, 5k/yr daily driver.

I'm semi-competent, DIYer. Cleared a P400 code by cleaning the EGR system. Can handle some non-electronic work. Replaced/rebuilt waterpump, timing chain, power steering gearbox, belts, upper/lower gaskets on Jeep ZJ last month.

Sulaco

Oh no.

Sounds like the head gasket gave out. My c280 did this. I overheated it once. After that it would run fine the first few miles but after it warmed up the gasket would expand and create same situation you're in. Don't drive it like that. Period.

Twichel04

Next time it starts doing that, do a compression test on it while it's still hot. You can "rent" a compression tester at Autozone for free if you don't have one already. Remember that just because you don't have any coolant/oil mix, doesn't mean the head gasket is not blown.

But, all that being said, 100*c isn't really all that hot for an engine. Most engines run around 200*F. 100*C = 212*F. Mine is almost always closer to 100 than it is to 80. Then again, I live in Florida... Its already nearly 100* out side before I even start the car, lol.

Sulaco

the only mix I was getting with my failed head gasket was coolant getting into the combustion chamber. my coolant and oil were clean.

that smoke trailing you indicates you were burning coolant in the combustion chambers... when it's running rough now, can you go back and sniff the exhaust? the sweet smell of antifreeze burning is a dead give away.

Super B

And if it's really blown you can open the coolant overflow and bubbles from compression will show. I'm working on a bmw right now that over pressurized the coolant system and spit all it's coolant out. Thankfully the cap was in good working order and let the pressure off... No coolant in oil either.

CigarXO

Great & QUICK replies - thanks.

Sulaco: Gray smoke on original overheat only. Yesterday's drive, 1hr each way, just led to rough idle and higher running temps. There is a distinct odor, not an oil burn - don't know if I'd call it sweet :-) just worrisome.

Twichel04: My temps are usually closer to 80-85 with AC on. Now 95-110, so noticeable change. Have not had a chance to compressor check yet. I do own a gauge. What am I looking for?

Super B: Original overtemp blew pressure off the reservoir top. It was replaced, but I am still loosing coolant. Must be to the combustion side now. I'll look for bubbles.

I have identified the leak area (common in several C36 forum posts) as being the front left corner area of head gasket / timing cover. I thought I had a lower block/oil pan gasket leak originally found during my EGR tube cleaning and garage puddles. Thought I'd defer.

SO - I'm trying to decide if this is a DIY project for me or more mechanic worthy (don't need the expense or time drain as I'm unemployed). If I can get through this with just replacing whole parts/seals/gaskets, I'm probably okay though it will take me 3x longer than you guys. If it requires guaging/setting/aligning valves, pistons, special tools, electronics - it is probably for a trained mechanic. Thoughts???

This feels familiar as I have a '98 Jeep 5.9r which developed a timing cover/water pump leak. I pulled/replaced/sealed fan, water pump, timing cover/chain, valve covers/gaskets. I rebuilt power steering diff. while in there. anything deeper = too hard

I've started to look for replacement parts - let's say its just the gasket/seals - but, already see numerous versions/kits/mixes. Any guidance on what all you'd replace while pulling parts?
* water pump was replaced '06
* most hoses look pretty good
* replaced topside vacuum tubes with EGR repair in April

Thanks!!!

Sulaco

The head gasket job isn't that bad. Remove exhaust, intake, valve cover. I removed timing gear to pop the chain off. Made sure not to turn the cams or engine to keep timing at tdc. Pulled timing cover then head. Cleaned the ever loving crap out of the surfaces, valves, piston heads, applied new gasket and used new head bolts, exhaust gasket, valve cover gasket, plug gaskets, reassembled and done. Took me four days working slowly and carefully. Only DIY I had done before was water pump!

There are lots of posts online about m104 head gasket DIY but pay attention to the ones specific to c36 because timing is different and the timing marks are not right. Otherwise I think you can do it, having worked on a lfa 360 like that.

CigarXO

Sulaco,
I'm sure I'll be doing a lot more reading to learn the task - heck, that takes as long as the job usually - but, did you have to pull fan, fan clutch, etc. off front to get to timing cover/front?

Did you find a gasket kit? vs I usually find I failed to order some seal/gasket and get delayed 3-5 days. I'm seeing a lot of versions already.

Anything else specific to C class AMG you remember? I'm afraid my fan clutch is also bad. with my Jeep, the one version I have had electric vs pressed-on fan AND high-volume water pump vs norm.

Sulaco

yes, the fan and clutch need to come off. It's not pressed on, but you'll need something to hold the clutch while you bust loose the bolt. I used a big strap wrench.

Can't say much as to a gasket kit, I did this job in like 2005. I just ordered a head gasket kit which, if I recall, came with head gasket, exhaust manifold gasket, intake gaskets, timing cover gasket, and a few other odds and ends. Here's a link to one:
http://www.autohausaz.com/search/pro...20Gasket%20Set

You'll need 14 of each of these:
http://www.autohausaz.com/search/pro...%20Head%20Bolt

Some people go ahead and replace the chain guides while they're in there (depending on your budget you might want to consider doing the timing chain, but honestly I've never heard of an m104 needing a new timing chain, plus it will up the scale of this DIY job a good bit, because you have to hand crank the engine and throw the timing off to install it, which obviously would require being able to get the rotating assembly and the cams back in timing which is beyond me):
http://www.autohausaz.com/search/pro...n%20Guide/Rail


Now, you'll find some DIY's out there who completely disassembled the entire head, including cams and valves. I DID NOT DO THIS. Once again, because I did not want to screw with the timing.

I think I even left my exhaust manifolds bolted to it, if I recall correctly! I left cams in place and was careful not to turn them while I was pulling/cleaning/placing the head. I unbolted intake and left it in the car. I didn't want to remove all that, especially the throttle body that might have a failing wiring harness (this might also be true with your car).

AutohausAZ-Mike

Sulaco,

Thank you for mentioning us, much appreciated!

If you guys have any questions regarding certain parts, please feel free to ask.

Good luck with the repair and hope the car will be back on the road soon.

AutohausAZ.com

CigarXO

I did conduct my Combustion Leak Test and found no compression gases to be in the coolant system. I'm hoping that's a sign my gasket is leaking - as visible at common front left of engine block near timing cover - but no significant damage.

The old school newspaper test of the condition of my fan clutch brought it to a stop. It also spins somewhat freely when spun by hand. This is probably the cause for the overheating and possible area of coolant lose?

The compression check - conducted by a novice - yielded:
1 - 164
2 - 152
3 - 155
4 - 170
5 - 168
6 - 172
How's this look? Can't find a reference to compare...

I am finding oil on the spark plugs. I'll replace valve cover gasket and seals as I replace head gasket.

I'll be moving into dis-assembly soon if you have a good thread for the repair/build. I am most concerned about maintaining the Timing/Cam positions so this doesn't get more complicated. Any hints?

I'm going to focus on seals/gaskets - is there any other wear/tear parts I should look at replacing while disassembled. Looked at tensioners, tc guides - but starting to get too expensive. Thoughts?

Twichel04

Your compression numbers look ok. Nothing there throwing a red flag for me when it comes to head gasket issues. You're fan clutch COULD be your issue with over heating if your electric fans are also not working. My fan clutch is bad too, but I don't have an overheating issue even in Florida summer time, however, both of my electric fans do work.

Your fan clutch would have nothing to do with coolant loss though. Are you seeing actual puddles or dripping, or are you just noticing that the level is dropping with no apparent leak?

How do your hoses look? Take the belt off and spin the water pump, note any play in the pulley or odd noises. Did you replace your coolant recently? Was the coolant system bled? Air in your cooling system could be a contributor to your over heating.

CigarXO

Finally got down to my head gasket. Leaks on front "triangle" area and back - as traditional.

Here's a few shots of the condition. Any thoughts?

Mike51809

That gasket has had it. I just did this job about a month ago on my 36. Make sure that you get the proper head gasket! It has a special hwa part number for the larger pistons and higher compression. I couldn't find one online and bought one through the dealer

CigarXO

Mike51809 -
Thanks for the heads up. After much anxiety about the special gasket issue, I did order a Victor Reinz gasket kit #02-28975-02 associated with part number, 1040103220 Cylinder Head Gasket Set, which then I went to the VR online .pdf catalogue and checked again. The kit/gasket is an individual listing for the C36 AMG and identifies the diameter as 91mm.

How much more did you do?
- Injectors
- Valves
- Machine the head

Any hints on cleaning? I'm thinking its just a lot of elbow grease, engine/carb cleaner and plastic scraping from here...

Mike51809

Very nice! Mine didn't quite do what yours did. I just cleaned the head and put it back on since it never actually blew and overheated. A rubber disc on a wiz wheel will help a lot. I Resealed all of the injectors. I took that rubber green pad with fingers to the valves and the entire head along with the block to clean it up. Oven cleaner kind of worked on my block but it still looks crappy. Also I did use some black mercedes silicone on either side of the head gasket and the oil pan gasket for extra insurance. I'm about to do both sending units and the fuel pump next week... Good luck!

CigarXO

Focused on the engine bay, cleaning the more accessible bay and cylinder head surface with Gunk engine degreaser, CRC brakleen and Gumout carb cleaner; soft metal gasket removal tool from Harbor Freight, plastic scraper(useless), towels and elbow grease. Insured surface stayed damp like wet sanding to reduce chance of scarring.

Before pic:



After pic:




Then cleaned/purged the EGR tube of build-up and cleaned the top timing belt cover of grime and sealant. I didn't think you were suppose to use sealant on the top cover surface to surface? Any advice? There appeared to be a light sealant application around outer edge and in bolt holes.

Tomorrow will be more cleaning and prep. I'm waiting on a local machine shop to give me a quote on clean, machine, rebuild the valves and a local injector shop to price flow and rebuild before I decide if I go further. Most parts on order or on hand.

Super B

Looking really good! Getting to the downhill side of things.

CigarXO

Continued cleaning and prep. Focused on mating surfaces of cylinder head and valve cover.

Before:










After:

Yolo-MBenz69

I have an 06mercedes-Benz c280 so wile driving my car over heats but when I put the heater on high the temp stays a lil over 80 but gets no higher . What could be the issue ? Please help

CigarXO

Yolo -
The heater is acting as an auxiliary radiator, or cooling system, thus indicating your primary system is probably the place to start your investigation.
1. Any recognizable loss of coolant?
2. When the car is running at normal/high temps - carefully check radiator hoses to feel for circulation. A failed thermostat could be preventing the cooling system from operating.
3. In my case, the thermostat had failed; but due to overstress from the primary cause being a failed fan clutch and bad pulley. Is fan operating? When off, you should not be able to freely spin the fan as there should be friction in the clutch (assuming your 06 is not electric?). Another check is to stick a rolled-up newspaper in the fan when operating. If the paper can stop it -then probably bad clutch.

Hopefully, this gives you a place to start. There are much more knowledgeable mechanics here than I. Good Luck!
CigarXO

Yolo-MBenz69

Well the coolant is still full and i just replaced the thermostat couple of months ago . So theres no leak could it be a bad waterpump?

CigarXO

Yolo -
While it is possible your new thermostat is inop, move to the next step of investigating the water pump. With the engine operating, you can squeeze the radiator hoses to determine if the pump is circulating. You can also observe/listen - which might reveal a bad pulley bearing on the pump. Use a mechanics stethoscope to improve your ability to trace noises. I'll assume the fan is operating

Yolo-MBenz69

Yes the fan is still running .

CigarXO

My fan ran also, but not effectively. Again, check for flow through radiator hoses and check fan with newspaper and check clutch by spinning. If none of this helps you diagnose, head to a professional.