Cooling Fans

Does your temperature gauge climb in traffic or in the pits, even though it stays fine at high speed? Then it's typically the fan that needs to pull air through the radiator. Here we've gathered electric cooling fans, fan shrouds, controllers and fan blades for street cars and projects with extra heat load.

What does the cooling fan do?

At high speed, the airflow from driving forces air through the radiator. In traffic, at idle and after a session on track, it's the fan that keeps the airflow going instead. An electric fan only runs when it's needed and can remove the mechanical load that a belt-driven fan puts on the engine. A fan shroud directs air across the entire radiator surface rather than just the area directly in front of the blades, which can give more even cooling.

How to choose a cooling fan

Diameter alone doesn't determine cooling performance. Look at several factors together:

• Airflow: Mishimoto, for example, offers both Race Line High-Flow fans and models with curved blades, so compare the stated data rather than name and size.
• Space: Measure the distance between the radiator and the engine. A slim fan can solve tight packaging.
• Airflow direction: Puller mounting behind the radiator or pusher mounting in front requires the correct direction of rotation.
• Power: The fan needs a relay, fuse and wiring that match its current draw.

If you want to decide for yourself when the fan switches on, take a closer look at fan controllers.

Installation and interaction with the cooling system

The fan can only remove the heat the radiator is able to dissipate, so consider it together with the radiator and the rest of the system. Some kits combine shroud and fan, such as CSF shrouds with a SPAL fan, while others are mounted with brackets or clips. Check the dimensions of the radiator core before ordering, and regularly inspect connectors, relay and bearings, and make sure the blades are free of cracks.

Frequently asked questions

Should the fan be mounted in front of or behind the radiator?

A puller fan behind the radiator is typically the most efficient, because it doesn't block the airflow from driving in the same way. Pusher mounting in front can be necessary when space is limited. Check that the fan is available for the desired airflow direction.

Can I replace a belt-driven fan with an electric one?

It's often possible, but it requires space, a power supply with relay and fuse, and a controller that switches the fan on at the right temperature. The alternator must also be able to supply the extra current.

Why does the engine get hot even though the fan is running?

The cause can lie elsewhere in the cooling system, such as a clogged radiator, air in the system or a faulty thermostat or water pump. If a fan shroud is missing, the air can also bypass the radiator surface.

What does a fan controller do?

It switches the fan on and off based on coolant temperature, typically with an adjustable switch-on point. This can keep the temperature more stable than a fixed thermo switch and prevent the fan from running unnecessarily.