The V8 Owners Forum -

Hello all,

Should I be able to move the water pump pulley by hand on my GEMS efi engine??

Thinking the belt isn't tight enough, but as I don't have a belt tensioner on the system, its hard to know what is tight enough.

Have some cooling issues, and I'm not sure the pump is giving 100% if the belt is slipping.

I have heard of people knurling the flat area of the water pulley for extra grip?.....anyone got or done this to good effect?

Its also a new poly 7-rib belt, and I've already tighten it a few times.....

No - you shouldn't be able to turn the coolant pump pulley by hand and the belt slip -
If you turn the pulley it should turn the engine over.

Tom.

If the belt is incorrectly tensioned (slack) the alternator will protest way before the water pump i.e screaming its head off especially when a load is applied to the battery post starting or headlights heater on etc

Belt wrap around the pulley is also very important - do you have enough wrap?

Post a photo of your belt routing - I've seen quite a few belt routes with the water pump barely deflecting the belt and this is not enough.

Tom.