Pulley Sizes And Cooling

[Guest 66olds]

Because I was missing a water pump pulley I had to buy an after market aluminum one. When I went to bolt it on it hit the stock crack pulley so I bought the matching aluminum one. When it came I put it on but its half the size of the stock one if not smaller. My question is, would that make a differnce in how the car cools? Would the water pump have to be at a certain speed to cool properly? If I am stopped at a light or in traffic it does heat up a little but cools down to about 180 when I get going again. Diesels like crazy too when it gets warmer around 220 or so. I am looking around now for a stock water pump pulley to put back and see how it goes. Any thoughts or suggestions would be greatly appreciated thanks.

[Guest 66olds]

Forgot to mention I am not running a stock fan I am using a 16 inch electric fan

with the flow coming from out to in towards the motor.

[rocketraider]

A smaller pulley is going to turn the water pump faster. It may be circulating coolant thru the engine and radiator too quickly to pick up heat and then reject it off the radiator.

Check your timing too. If it's retarded it can contribute to overheating at idle. You may need to check the distributor curve rather than just jacking up the base timing, esp since you already have dieseling issues.

[Guest 66olds]

The aluminum crank pulley measures 4 3/4 inches and the stock crank pulley measures 7 7/8 inches. Water pump pulley measures about 6 inches. I think the smaller crank pulley is really under driven and may not be circulating the water fast enough through the system. Wouldnt the smaller crank pulley turn the larger water pump pulley slower? Thanks.