Aux fans running engine hot
 

W124 1995 E320 124,000 miles.
My car is running hot (about 100C+) and both aux fans are
runnning on high.
When the engine is cold the fans are not running. With a hot engine they run high, I tried it with the climate control off-same effect. The clutch driven fan is working Ok.
I would suspect the temp sensor if it wasn't for the higher than usual engine temps.
Is it the water pump?
Thanks in advance.

Check thermostat
 

I'd check (replace actually) your thermostat first. At 124k miles - it wouldn't hurt to change it. It could not be opening fully - causing your woes. This shouldn't be that expensive.

If this has no effect - Thoroughly clean the cooling fins of your radiator.

If this has no effect - you may want to have your cooling system drained, flushed with a citrus "decalcifying" solution (MB makes such a product, I believe) and fill with proper coolant (the red MB stuff - NOT the green stuff).

Your coolant temp sensor sounds like it's working fine - as it is activating the fans when they are supposed to come on.

Let us know how you do.

Regards,
Troy
1995 E420 72k

Well Troy was right, the themostat was stuck in the closed position. I boiled it out of interest.

I put in a new thermostat and everything is working -
the engine runs at about 80C. I'm going to replace all the radiator hoses as a preventative measure.

I think that having the car sit for a while when I replaced the evaporator caused some of these gremlins.

Thanks

englishman