Belt-Driven Fans

Most factory-installed fans are belt-driven, meaning they function by pulling power from the engine. Because this type of fan can deplete horsepower and diminish fuel economy, choosing the right model is of the utmost importance.

Fan Clutches

Before getting into the different models, it's important to note how belt-driven fans work. The fan clutch is an important component of most belt-driven systems. It ensures that the fan is engaged at low speeds or high temperatures to provide adequate airflow to your vehicle's cooling system. Then, at high RPM or low under-the-hood temperatures, the clutch disengages the fan to remove any unnecessary load on your engine.

Two Basic Types of Fan Clutch

Thermal Fan Clutches

Use thermostatic coil to control fan based on under-the-hood temperature
Engage fan when temperature reaches a set point
Disengage fan once temperature drops sufficiently

Non-Thermal Fan Clutches

Sense shaft speed of water pump to control fan based on vehicle speed
Engage fan at low speeds when additional airflow is necessary
Disengage fan when vehicle speed allows for sufficient airflow

Fan clutches are vehicle specific and can be found in our Fitguide. Because a clutch will take up a fair amount of space inside your vehicle's engine compartment, certain belt-driven fans are designed to work without them, allowing more room on custom engines.

Types of Belt-Driven Fans

Race Fans

Move a large amount of air when the engine's RPMs are high
Great for anyone who has a need for speed
Replace factory fan and clutch
Save space and reduce weight
Minimize engine loading by not relying on clutches
Rated up to 8,000 RPM for racing conditions

Flex Fans

Perfect for engine swaps and custom work
Low-profile design fits in tights spaces
Different styles and colors let you customize the look of your vehicle
Large surface area pulls more air than most factory models
Narrow blades flatten out at high RPM to minimize engine load

Fan-Clutch Fans

Operate the same way as a factory model—makes a great replacement
Fits most factory clutches
Made of heavy-duty steel for maximum durability and longevity
Is available as either standard or reverse rotation to meet your vehicle's individual requirement

Fan Spacers

Because the distance between a vehicle's water pump and radiator can differ depending on the level of customization, it may be helpful to invest in a spacer for your belt-driven fan to achieve proper fan placement and maximum cooling.

Diagram #1 (left)
If you are installing a fan with a shroud, measure from the water pump's flange to the edge of the mounted shroud and add 3/4" for your spacer length.

Diagram #2 (right)
If the fan you are mounting does not have a shroud, measure from the flange on your vehicle's water pump to the radiator. Subtract 3" from that measurement to get your spacer size.

Fan spacer measurements 1) with shroud: from water pump flange to shroud plus 3/4 inch; 2) without shroud: pump flange to radiator minus 3 inches.

Please Note:
When installing your new fan and spacer, be sure that the fan has at least a 3/4" clearance from the radiator, belts, hoses and pulleys. The range of adjustability on the spacer's flange allows it to fit several differently sized water pump flanges to ensure proper fit. Spacers are available in lengths ranging from 1/2" to 3".