Thermostatic Air Cleaner: Operation

When engine and ambient temperature are cold, below 68°F (20°C), the air door inside the control box will be closed to outside air. The thermostat senses the cold ambient condition and moves the air door to heated air only.

As engine warms up and ambient air temperature increases, the thermostat begins to move the air door off its heat-only position and toward the cold air only position. When ambient air temperature is above 93°F (34°C), only colder, outside air is allowed to enter the intake system.