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Which way to unscrew fan clutch from water pump?

23K views 17 replies 8 participants last post by  sparky1016 
#1 ·
2003 ML350

I have the tool to hold the water pump and the tool to fit the clutch nut.

It's tight.

Standing at the front of the car look at the engine - is it spun clockwise or counter-clockwise to loosen the thing?

Thanks!
 
#5 ·
Well actually, I think the nut is reverse-threaded, so you'd be spinning it clockwise to loosen. The engine also spins clockwise looking from the front. The fact is, you wouldn't be asking this question if you had to turn it counter-clockwise to loosen it now would you?
 
#11 ·
Fan and clutch have inertia. They resist torque. Clutch has right hand thread. Water pump spinning counter clockwise keeps it from getting loose.

In vehicles with water pump spinning clockwise fan clutch has to have left hand thread.

Left hand thread is easy to identify by groove cut across tips of hex.

 
#17 ·
Fan and clutch have inertia. They resist torque. Clutch has right hand thread. Water pump spinning counter clockwise keeps it from getting loose.



In vehicles with water pump spinning clockwise fan clutch has to have left hand thread.



Left hand thread is easy to identify by groove cut across tips of hex.





After all these years I didn't know the left hand thread nut had those notches in it for identification. Ya never stop learning, thanks Witek


Sent from my iPhone using Tapatalk
 
#12 ·
But the water pump spins clockwise... (looking towards the engine). But honestly I'm not sure anymore, but I can explain why the fan is loosened in the direction of rotation. The fan blades cause a "reactive" torque in the opposite direction of engine rotation (+ their inertia also, but that gets overcome once the blades start spinning, the air resistance would be the larger effect), so if the engine rotates clockwise, then the fan is tightened counter-clockwise, because it will be constantly trying to tighten itself when the engine is running.
 
#14 ·
Guys, you are confusing the direction of the rotation of the belt with direction of the rotation of the water pump. Belt turns clockwise. Pump turns counter clockwise.....
Look at Witek's PDF properly & imagine the belt turning clockwise. The belt turning clockwise rotates the pump counter clockwise.
 
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