Cooling fan

[rosie5golf]

Help !! My cooling fan starts up as soon as I start the engine. I've checked the water, that's fine, I've checked to see if there is a temp sensor I could replace, there isn't one. Water seems to be circulating as the top hose gets hot and the water temp is just above 80 degrees when running.
I would appreciate any help.

 

[anderoo]

Is your aircon left on 'auto'? I was worried about the same thing when I first got my car, turns out if the aircon is on the fan will start. I leave mine on auto, so the fan is always running.

 

[Joderest]

Does fan run after engine switched off ?
This could well be the temp sensor located in Thermostat housing giving false information to ECU.
Just a good guess !!!!!!

 

[mersum1es]

common symptom if ecu has no/undervoltage. Check all fuses. Age of car? W210 has easily malfunctioning fan control module.

 

[topdown]

It is probably the aircon pressure switch on the condenser. To confirm it needs to go on a star machine. If it is the aircon gas needs to be removed to change £150 plus parts.

 

[OneForTheRoad]

my duff interior air temp sensor sent my w211 fan nuts . i replaced the sensor and reset it using a mb2 from icarsoft and its been fine since .

 

[rosie5golf]

Does fan run after engine switched off ?
This could well be the temp sensor located in Thermostat housing giving false information to ECU.
Just a good guess !!!!!!

Hi,
I checked for the temp sensor and there doesn't appear to be one, just a lead sitting with a blanking plug in the end.

 

[rosie5golf]

common symptom if ecu has no/undervoltage. Check all fuses. Age of car? W210 has easily malfunctioning fan control module.

Mine is a 2008 W211 diesel. Can't seem to find the fuse for the fan.

 

[rosie5golf]

It is probably the aircon pressure switch on the condenser. To confirm it needs to go on a star machine. If it is the aircon gas needs to be removed to change £150 plus parts.

Thank you. Air con working fine.

 

[OneForTheRoad]

Mine is a 2008 W211 diesel. Can't seem to find the fuse for the fan.

Mercedes E Class w211 – fuse box diagram | Auto Genius