Viscous Fan Explosion

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Originally Posted by BusinessConnected

I guess my major cause of confusion at this stage is why has the Coupling fallen off... surely if the Fan has died it should have just stayed on...

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Agreed. I've never heard of one unscrewing before.

Hi

I have read of a tractor fan going backwards when the viscous coupling faulted.

It was if the fluid inside the couplings housing balled up and as the inner drove the balled up material, the outer was driven the opposite direction.

Try another make of viscous coupling and fan.

The only way the clutch will unscrew is if the fan pulley suddenly stops. If the fan shed blades which momentarily jammed the drive belt the coupling would spin off. I have seen a coupling do that when someone dropped the clutch in the wrong gear. The thread simply hadn't time to lock tightly.

Well I've driven another 275km on the Same Viscous Coupling/Old Fan Combination and everything has been working well.

The Roar from the Fan when taking off from a Standing Start indicates to me that the old Coupling was knackered because it's moving much much more air...