[keith4.7]

2002 Dakota Crew Cab. 208500 miles. Purchased new. 4.7 Automatic

Every once in a while, my Dakota starts roaring from the engine. Sound like a fan noise as it increases and decreases with rpm. Thought it may be the fan clutch.
What is the purpose of the electric fan in front of the ac condenser.
I know noises are hard to diagnose over the internet. Just wondering if anyone else has experienced this.

 

[valiant67]

The Dakota was really bad with fan clutch needs. My 1999 roars when the AC is on and you start moving after it's been idling a while.
I'm not familiar with the 4.7 setup, but the electric fan probably is there to boost efficiency of the mechanical fan at lower RPMs.

 

[ImperialCrown]

It is a cooling helper fan with A/C on and towing in desert mountains (or other high loads) in higher temperatures.
If your cooling system is in good shape and the vehicle only sees light to moderate loads, you may be able to do away with the mechanical fan completely. It unscrews (the same direction as it turns) from the water pump pulley after removing the upper shroud. The electric fan can handle most normal cooling requirements.
Keep the mechanical fan handy if you find you need to re-install it. It is much quieter without it.