Overheating???

I am new to the Mercedes world. My friend let me have his 1986 300e because he went to live in russia. Well the car runs great but in hot weather and stop and go traffic, it heats up to about 115 C* out of a posible 120. Now my manual says that under bad conditions, the car will heat above normal, but 115 C*??? I don't know. Can someone tell me if I got something to worry about, or am I just paranoid?? :confused:

Thats not normal unless u live somewhere really hot

Based on the temperatures you should be concerned. The year of your E-Class brings the idea of High Milage to mind, however, you never stated that in your post. I would suggest a close look at your radiator and thermostate to include a pressure flushing of the system due to the propensity of the system to run hotter more over 150K miles. You will find that many High milage E-Class will need to have the radiator changed and system flushed. Your temp problem is common under such conditions.

The 300E uses a visco fan clutch. If the fan clutch fails, hightemps at idle can occur. There is also a 212 switch on the engine, which is supposed to turn on the auxilliary fan if temps approach 120C. If the engine gets hot and you don't hear that fan, then this system might be in need of repair also.
This is assuming that the radiator and thermostat are ok, as rogerw suggested.

Same problem here.

This is what I did to fix the problem at no cost.
Unplug the aux fan then connect a two core wire put one to ground, for the live I used the D on the fuse box. That way the aux fan runs as soon as you turn on the ign. Just make sure the LIVE wire you connect turns the fan in a CLOCKWISE rotation as you are standing in front of the car. It sure stopped this stupid overheating problem

Had a similar problem with my 87 300E. Turned out it was the voltage dropping resistor in the aux fan circuit controlled by a pressure switch off the air conditioning compressor. It was open so the fan didn't come on at all until the temp got to 115 degrees C. Replaced the resistor and now temp stays between 90 to 95 with the air conditioning running and that is in Phoenix during August.

yup, fan not kicking in is the problem... when you drive on the freeway, air automatically gets into the radiator, but in stop and go, since your not going fast, your fan kicks in and draws air in... Check the fan first.. most running temps are usually 75-90... if your fan works, check the thermostat, followed by coolant itself...

Had this problem on my 97 E200, Manual, No Aircon, 70K miles FMSH. Overheats when Idle or in slow traffic, putting heater on hot helps but eventually runs to red area on temp guage, no loss of water if I stop before red temp (120 Deg) reached. Insert Corrugated Card whilst engine idling, if it stops its more than likely the "Vicous Coupling" (Fan Clutch or Disk within Fan Housing £75 inc VAT). Remove few bolts which secure Fan onto engine and replace. Try Card test again and Fan should keep going. Seems to sorted out problem on mine. Replacememt took 20 mins and £20 labour.

Had same problem with my 91 300e for years. Tried all the usual fixes with no apparent luck. The water pump finally gave out. A new factory replacement pump solved the overheating problem. The car rarely runs above 85C even in heavy traffic.