I was just wondering about how the viscous fan is supposed to operate. With the car off is it supposed to move freely? Would this mean a clutch failure? Can someone explain to me exactly how it is supposed to operate and what are the symptoms of clutch failure? Thanks!

it's supposed to do that.

The main fan of the Zed is driven by a socalled (oilfilled) thermal fan clutch.

On this clutch is a small bi-metal thermostatic coil that will sense the heat from the radiator and engine and activates or de-activates the clutch accordingly.

Once the engine (and radiator) starts to radiate a certain amount of heat the clutch starts to engage to provide maximum cooling and once the engine is still cold or at normal temps, the clutch is disengaged for the most part.

 

On a Zed the clutch should start to engage when coolant temps reach approx. 90 degrees Celcius.

You should hear a clear blowing sound coming from the fan (the car should start to sound like a giant vacuum cleaner)

It usually also makes this sound when you start your car after it has been standing still for a while, but the clutch slowly disengages once the oil in the clutch has warmed up a little.

 

If you can't hear your main fan while the engine is hot, the clutch is not engaging/functioning (common problem on Zeds) and it should be replaced.

 

-Eric