PeachParts Mercedes-Benz Forum - View Single Post

cnev300d · #8 12-11-2007, 09:22 PM

Thanks for all your replies. I'm still at a lost as to why my 85 300d is overheating.

I have posted this previously here: http://www.peachparts.com/shopforum/showthread.php?t=203337

Ok, this is what's happened since then.

I have drilled a couple of holes in the t-stat and the car has been running hot, but not overheat. The temp gets up to 110 C when the hot air is not blowing out.

When hot air does blow out, the temp is a normal 80 C. The hot air only kicks in occasionally, but most of the time, it just blows out cold air! My center vents do not blow out any air. When hot air does blow out, I hear a brief grinding noise in the gauge cluster area like something is opening.

I have also checked out the monovalve. It seems to be working when I tested with a 12v battery charger and the rubber diaphram is ok. I have also tried a different but used climate control module.

History of car's cooling:
1. Car does not show temp when I first bought it.
2. Replace t-stat, temp shows normal for a couple of months
3. Car had a couple overheating episode, coolant runs low, etc.
4. Flush out old coolant
5. Drilled holes in tstat, car now runs hot when no hot air blows out.

Can anyone tell me what's under the dash board besides the heater block? I'm thinking of removing the t-stat and bypassing the climate control all together and see if that helps.