W124 Cooling FAN running all the time

[ADY1983]

Hi I have just dropped a new Engine in my 300CE and the cooling Fan is running all the time. I dont remember it doing this before, so what have i done to cause this?? How can i stop it?? when i accelerate it sounds like a plane taking off

 

[Asif Kazani]

Check the thermo fan switch. They tend to malfunction upon aging. Usually the pins inside the solenoid get stuck in the on position.

 

[MangoMan]

Just an idea but try spining the fan when the engine is stopped, if it spins then it's not the clutch mechanism so most probably the switch. If it doesn't move I would say it's time for a new coupling.

Well, that what I think anyway.

 

[shandy]

Your car is fitted with a viscous fan coupling and from what you say this has locked up, it is not serviceable and will need to be replaced. About £60+ for the part and an hour or so to fit.
Geo.

 

[TKB13]

I'm inclined to agree with shandy, coupling seizure. You could try the simple 'carrot test' (see if you can stop the fan at idle speed with a carrot). If you end up with half a panful of soup-sized pieces then the diagnosis is confirmed!
But for goodness sake watch your digits!

 

[ADY1983]

I'm inclined to agree with shandy, coupling seizure. You could try the simple 'carrot test' (see if you can stop the fan at idle speed with a carrot). If you end up with half a panful of soup-sized pieces then the diagnosis is confirmed!
But for goodness sake watch your digits!

Thanks ill give it a go