Air Cleaner - Thermostatic: Operation

When underhood air temperature is below 100°F (38°C), temperature sensor valve is closed. This directs manifold vacuum to air control diaphragm, which opens air control valve. With valve open, pre-heated air flows into air cleaner from heat stove.

When underhood air temperature is 100-127°F (38-53°C), temperature sensor valve is partially open. This reduces vacuum applied on air control diaphragm and results in a smaller air control valve opening. In this condition, intake air is a blend of direct underhood and pre-heated air.

When underhood air temperature rises above 127°F (53°C), temperature sensor valve opens fully to cut off all vacuum to air control diaphragm. In this condition, air control valve is closed and only underhood air flows into air cleaner.