Engine overheating due to radiator fan rotation in wrong direction

A radiator is a heat exchanger that tranfers the heat in the coolant circulating through it into the environment through the fins.

Radiator fan is the fan that is placed in front or behind the radiator to force air through its fins for efficient cooling.

The radiator fan pulls air from the environment towards the engine to cool the coolant in the radiator and the engine block. The direction of rotation depends on the orientation of the fan's blades.


Types of radiator fans

1. Push fans

They are positioned in front on the radiator and they push air from the environment (front of the car) towards the engine.

2. Pull fans

They are placed at the back of the radiator, in-between the radiator and the engine. They pull air from the environment (front of the car) through the radiator.

Both types of radiator fans direct cooler air towards the radiator (to cool the coolant) and the engine (to cool the engine block).

At times, overheating occurs because the cooling fan is not rotating in the correct direction, causing inefficient cooling.


Causes of radiator fan wrong direction of rotation

1. Wrong electrical connection of power to the fan

This has to do with interchanging the positive and negative terminals of the fan with that of the power source. If it is reversed, the fan will spin in a reverse direction.

2. Installing incorrect fan

There are different fans with different blade orientations. Sometimes, it is possible for a fan to fit into position yet have different blade orientation which makes it to blow air in the opposite direction.

3. Misplacing the position of the fan

This happens when a push fan is placed behind the radiator or when a pull fan is placed in front of the radiator. This also makes air to move in the wrong direction, causing inefficient cooling.

It might be difficult for a non-tech person to troubleshoot overheating fault due to wrong cooling fan direction of spin because it might be assumed that all is fine with the fan since it is turning. For this reason, it is good to always take note of this whenever radiator fan is being replaced.