Cooling system acting funny. PLEASE HELP!!! - PeachParts Mercedes-Benz Forum

maddogg20 · #1 10-31-2006, 02:14 AM

MY benz is acting weird. Its an 83 300td, anyway it has a New Tstat, electric cooling fan, new coolant, etc, upperhose is hotter than can be bottom is cold and air coming out from the fan is semi warm, but it will still stay right around 100C even when the air outside is cold as ice. Could the rad be plugged? I think its the stock one, but the weird thing is, when the cars like at 100C IF I turn the heater to max the temp needle dives like down the the 80C mark. Any ideas? Also, I burped it the other day but its still running too hot for my liking.

BenQ · #2 10-31-2006, 03:16 AM

The temp on my car will run that hot at times (83 300sd). I'm not concernrd about it. If the rad is plugged the temp. will get hotter and hotter when the car is put under load. (like on a fast trip down the highway).
I would think that you are getting your tenp. reading from the guage in the dash. Have you tried checking your tenp. with an infarred temp.guage to varify that the temp. is actually high.
I had an Austin Mini that seemed to run hot, turned out that it had a voltage supply problem to the guages and that all was fine under the hood.

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83 300sd
3 Fords

bgkast · #3 10-31-2006, 04:15 AM

I bet your temp sensor or gauge is off.

SootyPast · #4 10-31-2006, 09:44 AM

If the upper hose is really hot like you say then I would suspect that the gauge is accurate. Did you use an oem thermostat? Did you drop it by accident? I have indeed taken a few tstats out of the box and had them defective maybe 3-4 in 30 years. To me it sounds like a bleeding issue or a bad tstat. I would recheck as it is very simple to test.

maddogg20 · #5 10-31-2006, 09:31 PM

Naw I didnt drop it, Its actually a NAPA thermostat, but it looks just as good as the stock one, just not all red and stuff lol.

85chedeng300D · #6 10-31-2006, 10:01 PM

I don't know what's up with these cars man? My car, an '85 300D Turbo, has been that way since I had it. Runs hotter (about 85-100 degC) in the winter and normal hot (stays and holds at 90 degC) on summer days, doesn't matter whether interstate or city driving, uphill or downhill. But during summer, the gauge doesn't fluctuates as much as during cold weather. Right now that it's beginning to get cold here in the South, especially in the morning, my temp guage would rise up to 100 deg then drops to 85, then stays at 85, then gradually creeps back to 100, then drops back to 85, and so on, at any driving conditions, highway or stop and go.

#7 10-31-2006, 10:05 PM

Quote:

Originally Posted by 85chedeng300D

I don't know what's up with these cars man? My car, an '85 300D Turbo, has been that way since I had it. Runs hotter (about 85-100 degC) in the winter and normal hot (stays and holds at 90 degC) on summer days, doesn't matter whether interstate or city driving, uphill or downhill. But during summer, the gauge doesn't fluctuates as much as during cold weather. Right now that it's beginning to get cold here in the South, especially in the morning, my temp guage would rise up to 100 deg then drops to 85, then stays at 85, then gradually creeps back to 100, then drops back to 85, and so on, at any driving conditions, highway or stop and go.

That sure sounds like a "lazy" thermostat to me.

85chedeng300D · #8 10-31-2006, 10:21 PM

Quote:

Originally Posted by Craig

That sure sounds like a "lazy" thermostat to me.

...and so am I!