Previous Info:
Hi,
Thought I would relay this. Looks like my headgasket is going on my ’86 300E at 200k miles. No puddles and pressure test hot and cold found no leaks. No oil in water. However, the fluid was going somewhere -- the light was coming on at about every 300 miles needing 0.5 to 1 Liter fluid added. Exhaust was steamy at times and cold starts had a very lumpy idle as well.

So, not that I wont do the head gasket and upper end on this baby – I don’t really relish all that $$$$. So, I went for the $ solution to at least buy me some time. Bars Leaks. 1 bottle at $3.99. So far about 1,000 miles and no fluid loss. No overheating, no steam, and cold idle almost perfect.

New Info

I am again losing coolant. I have a few questions. Any help greatly appreciated. Car is early 1986 300E M103 204k miles.

1) The radiator cap holds pressure a long time – I have come home Friday night and not driven and checked the car stone cold on Sunday to find it holding pressure. Is this an indication of anything?
2) If I do decide on head gasket and head work, what do I need to have tested before hand to ensure it is viable to repair?
3) What can I expect to pay for head job, gaskets, possible chain and guides and the various other seals which are opened on this job.
4) Finally, is it worth trying a re-torque of the head bolts?

Thanks Again!

__________________
David
1986 300E Anthracite + ECodes + MB Mileage Award

You may have a leaking/blown head gasket, though I'm not convinced that you do.

Look at the thread at the bottom of this post. The detection method I pointed out was found searching the WEB one evening. One of the participants in this thread indicated that HG's can blow in a number of areas and that the method I listed was only good for one of them. Nonetheless, I believe it's worth a shot and there were others ideas kicked around in this thread. Consider what Gilly had to say in the last post. Is there oil in your coolant overflow tank?

You mentioned a 1/2 to full litre loss in 300 miles. I would be curious about the following:

a. How clean are your spark plugs? If you're cyls. are drawing in hot coolant, your plugs will get a "cleansing bath" and be cleaner than usual.

b. Is any leaking out the tail pipe on to the ground. Start it up in the morning with a pan underneath your tail pipe and let it idle for a good while. You'll get condensation when all is well anyway, but if you are blowing coolant out the pipe, you should notice it in the pan. If the pan's content is the same color as your coolant, then................

Technique To Determine If Head Gasket Is Blown/Leaking

__________________
Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"

Thank you and no, I do not have oil in the coolant.

__________________
David
1986 300E Anthracite + ECodes + MB Mileage Award

You said the radiator cap holds pressure, but have you pressure tested the system with the engine cold to see if it holds pressure and has no leaks?

I had that problem with a 1992 300 E and it turned out it had about 3 or 4 places where it was leaking coolant. The leaks were each very small and hard to detect, at least for me, unitl I pressure tested it cold. One of the leaks was from the o-ring in the thermostat housing and I recall some of the others were just from hose clamps.