Hi

I have a 1997 C180 and it seems to be over heating. I have checked the electric fan connected to the radiator and that works fine but I was told that the fan was for the aircon. I'm confused.. Can someone please help me.
What else should I check and has anyone got the electrical diagram for this car.

Thanks
Shabir

 

The fan is not just for the air cond. The cheapest and easiest is to change the thermostat. I found that about 75 % of the time that is it. Do that and if that's not the fault check back here maybe there is another idea.

 

Hi

I took off the thermostat and tested it (by boiling it in a pan) and it seems to be working fine because the thermostat opened when boiled and closed when removed from the boiling water. Since this isn't the problem can you suggest anything else.

Could it be an electrical problem? if so does anyone have the electrical diagram for the cooling system.

Cheers

 

I would replace the thermostat. It's cheap. The boiling test may not show you much. At 212 F it will open but may not at 87C. If that is not it then I would suspect the radiator. If the fans come on with the AC then they are likely working correctly. Take the top hose off and check the flow when warmed up but be careful and don't get scalded

 

when i turn on the AC the fan does not come on, infact the fan deos not come on what ever the tempurature is. I have been told by my Local Merc dealer that it could be the fan control unit (ESG control unit) but he was unable to tell me how to test it. Does anyone know how i can do this??? I thought if i knew which termanals to short to activate the fan that would prove that the ESG unit is faulty. Any ideas..

 

What do you define as "overheating" ??

Bazzle

 

when i say overheats i mean the temperature needle goes into the red.

 

you got a c 280 ..???

 

I have fixed it!!!!! the problem was the fan control unit. I asked my local MB garage to let me try a new control unit to see if it fixed the problem and it did. It cost me £120 (rip off) but it fixed the problem.
Thanks for your help.