Radiator fan always on - Help
 

Hello Friends,

The last week I have noticed that my cooling fan (the electrical one in front of the radiator) is always on. I´m not sure what to look for. Can anyone of You help me with some hints?

Many thanks in advance!

Mikael Westerberg
1984 500 SEL
Vanersborg, Sweden

Ooh And another thing while I´m at it. The engine stumbles and stutters quite a bit at cold starts and goes back to normal running after a short drive (as if it´s to lean). I guess that there is probably a sensor gone bad which makes the engine beleive it´s always hot but i just dont know which one to look at.

Thanks again/ Mikael

The top hose between radiator and the engine connects to hose connector. In top ot this connector the temperature sensor is screw in. Disconnect the plug/plugs connected to the sensor. The pug with two wires control electric fan. The first stage if temperature rich 105C and second at 120C. The temperature sensor is close and electric fan works continuosly when car is on. You can drive car temporary with out this sensor and later replace with new one.

Roman
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86 420SEL 225K

aux fan
 

Does it run LOW or HIGH? Make sure A/C is OFF. If LOW, refrig fan switch on A/C drier is bad or relay is stuck. If HIGH, Engine temp sensor bad or its relay is stuck. Find out first if the aux fan stops running at its particular speed by disconnecting the relevant sensor. If that does not work, try replacing or switching the relays. There are two relays for the aux fan...at least for my car and they are the same type. Hope this helps...

good luck,