SAE recommends evaluating off-highway cooling systems using the conditions of the actual installation, including all the heat exchangers served by the fan – not just the radiator. Caterpillar likewise recommends checking airflow restrictions, radiator condition, belts, hoses, coolant flow, and the fan shroud when investigating overheating.

1. Check the cooling pack

Start with the radiator, charge-air cooler, oil cooler, condenser, and any other heat exchangers in the airflow path.

Look for dust, debris, damaged fins, or contamination between the cores. Even when the front surface looks clean, restriction deeper in the cooling pack can reduce airflow. Caterpillar recommends regularly cleaning radiator fins to prevent clogging.

2. Check the airflow path

Make sure air can enter and leave the cooling system freely.

Inspect grilles, screens, guards, and ducting for restrictions. Check that the fan shroud is intact and correctly positioned. The shroud helps prevent air from bypassing the radiator rather than passing through it.

3. Check the fan and drive

Confirm that the fan is rotating in the correct direction and reaching the expected operating speed.

Inspect belts, hydraulic drives, viscous clutches, or other drive components for slipping, wear, or incorrect operation. A fan can be turning while still delivering insufficient airflow.

4. Check the fan against the system

If the cooling pack is clean and the drive is working correctly, the issue may be fan performance.

Fan diameter, blade pitch and configuration, speed, shroud position, and system resistance all affect the airflow actually delivered through the cooling pack. SAE research confirms that changes in cooler restriction alter the fan’s operating point and available airflow.

If overheating continues under load, the next step is to assess the cooling system as a whole rather than simply fitting a larger fan.

Inventive Air Designs can diagnose airflow problems and design fan solutions around the requirements of the actual application.