Anyone put an electric fan on a 99 tahoe (5.7L)? My 91 Stang saw a 2mpg improvement when I dumped the old mechanical fan in favor for an electric so I am wondering if anyone has tried it and seen an improvement in mileage...(not to mention less stress on the water pump)

 

I can see how electric can reduce waste on the engine power, but how does it affect the water pump?

We sometimes swap them in Jeep world to improve cooling at 5MPH when the engine is running hot, but its not getting air

 

The stock fan is mounted to the water pump. With the fan spinning (its not perfectly balanced) there is always a slight wobble. This puts stress in the water pump shaft and over time the water pump goes bad. Look where the 'weep" holes are on a water pump, along the shaft since the first sign of trouble tends to be the excess play between the bearings and the shaft...the two parts that get slowly beat to death by an out of balance fan. By going with an electric fan you remove the vibration caused the fan and extend the life of the water pump.

 

I could see that