Overheat fan

[Gambit]

On a normal car with a viscous fan the fan free wheels as the engine rotates and a heat sensor makes the fan engage. which normally produces a loud roar and then disengage as the temperature reduces to norm.

That's the basic view.

So why is it that my cars temperature gauge gets to half way and sits there until I switch off, regardless of beating hot sun and clutch controlling in a traffic jam. I don't recall ever hearing the viscous fan kick in, in the three years I've owned it. It never over heats or boils fluid.
I think it must stick out it's tongue and pant like Lightning McQueen.

[Martin F]

As far as i'm aware the viscous coupling is a progressive device, in that it will slowly begin to increase the resistance between the outer and inner pieces of the pulley. Which means you won't really here it all of a sudden lock up.

I did have a car where the viscous coupling went faulty and the fan was locked up permanently and it made a hell of a noise, like something about to take off, only on idle

As for the stock temperature gauge, it's pretty crap. My HKS electronic fan controller has a seperate temperature read out on it, and it can change by up to 20degrees and the temp needle hasn't moved at all.

[Mike_Mac]

Originally Posted by Martin F

I did have a car where the viscous coupling went faulty and the fan was locked up permanently and it made a hell of a noise, like something about to take off, only on idle

As for the stock temperature gauge, it's pretty crap. My HKS electronic fan controller has a seperate temperature read out on it, and it can change by up to 20degrees and the temp needle hasn't moved at all.

Agreed - the VC being stuck on and crap temp gauge were part of the chain of events that led to my HG going!