Daisy is TOO hot!!! W123 still overheating after replacing tstat and water pump????? - PeachParts Mercedes-Benz Forum

bcobbweb · #1 07-31-2008, 08:35 AM

Hi
Daisy is a 1981 300TD 250,000 miles (617952 engine; greasecar, but not run on wvo) who started going through water this past month, and whose temp gauge would go up to 120 degrees. So I changed the waterpump and thermostat (boiled new and old ones to see the difference - the old one didn't open as the new one did). Changed the hoses too, belts were fine.

While doing a diesel purge, after zipping everything up, the temperature went up to 80 after about 4 minutes, fluctuated a speck, and then climbed to 120 degrees within ten minutes and stayed there. Same old same old. No aux fan came on. Radiator was cool/cold as were the hoses (seemed completely empty). Engine, hot.

For what it's worth, the air filter was clogged with oil when I changed it, and only a few drops came out of the transmission line when I disconnected it. (cause for concern?? ATF level is fine.)
I'm planning on replacing the monovalve tomorrow since daughters (who take Daisy to college) said there was no heat. (but that shouldn't affect the overheating.)
Vacuum system had been "fixed" by a friend when Daisy refused to shut off in the early spring.

My current plan of attack is to:
1. open one of the hoses to see if somehow the radiator is blocked (unlikely since water was running through it).
2. Take off the overflow/coolant tank cap to see if there is some sort of air lock (although I doubt it because the system doesn't seem to be a closed one since there is an overflow hose).
3. Find out is there is some sort of secret control valve that regulates things. (help help)
4. Test the auxillary fan somehow to see if it works (I guess I'll start with the fuse).
5. Take it to a mechanic.
6. Take the girls out to college in my car.
Any suggestions in novice english would be appreciated. Thanks.

vstech · #2 07-31-2008, 08:46 AM

what's with all the benzworld links in your post?

vstech · #3 07-31-2008, 08:51 AM

first question. how did you refill the car with coolant?
second question, why did you take your transmission line loose? which lines did you open?
third, is more of a guess than a question, if you pulled the radiator out to access the WP, did you look through it? was it plugged with buggs??
it sounds like you did not fill the motor with coolant to me.
you have to fill the car with the engine end of the car as high as possible, and you have to fill through the upper radiator hose. then top off with the expansion tank.