1992 300-E runs hot
 

I took a trip to San Degio this passed weekend and I noticed in traffic the tempeture gauge going above 80-Centergrate. with the AC on. What is the normal running tempture for these engines with low millage to run at ? I have 36,000 miles on the odometer. Also What thermostate is recommened to run in this engine. I am goiing to change the collant and therostate and see if that helps first.
I also noticed that my AC works on low with the dail set to maz cooll. I am not sure if I am low on referigent being the car sat so long with its present owner or if there is a problem with the system. What do I check and How?

Thank You
Bob Geco
1992 300-E sportline

If your temperature is just above the 80C mark in hot traffic do nothing if you like it the way it is!!
Chances are your thermostat is not completely closing and your engine is running a little cool. IF you put in a new thermostat (87c is the standard OE Tstat) your car will run 90C in hot weather and traffic and as much as 100C with the AC on. You would have "fixed" it ;)

Oh, "Normal" running temp is a tick above 80C.

The normal operating range is about 80-105C. At 100C the mechanical fan clutch tightens, but it does not provide enough air flow at idle, so the temperature may continue to climb. At about 105C the auxillary electric fan(s) engage, and the temperature should drop quite fast to 100C where they disengage.

Continued low speed traffic will repeat this cycle until you get up to a steady speed above about 40 MPH when the temperature should drop to somewhere between 80 and 90 unless it is over 100F ambient.

Duke