Hi, </P>


My 1999 E320 temperature gauge goes up to 95-97C in traffic (at normal speeds around ~60 Mph its around 80C which seems normal to me). Even though I have read some posts saying that ~100C is normal for Mercedes, I still would like to confirm that. Right now the weather is quite cool here in L.A. but I am a bit worried about the next californian summer. We had outside temperatures of 100F + and I am wondering what will happen then... Is there any way to check if the enginge fan is working ? At 97C it did not run, which, if this 100C treshhold is normal would be ok, but otherwise? </P>

 

The temperatures you have given are normal operating temps for any mercedes. The fan on your car sounds like it is an electro magnetic couplng as you say it does not run around 97c. They are not supposed to, they switch on at around 100c and stay on until the temperature is at around 80c agian. You will hear the fan coming on and off in traffic as an audable thunk from the front of the engine, then a continous whir more audable when reving the engine or driving the car. This will come on for around one minute and will go off when the temp gauge has dropped to around 80c. You can test it by simply whatching the fan whilst the engine is ideling, if it does not come on at or after 100c there may indeed be a problem.

 

I believe the cut-in temp. for the aux. fans is 105 to 107'C. Your temps. are fine and when it gets hotter outside they will just turn on more often.