Automatic Hot Air Intake & Hot Idle COMPENSATOR: Operation
When intake air temperature is low, vacuum valve is closed. Intake manifold vacuum will act on heated air door diaphragm. This causes diaphragm to pull up and close cool air intake. As intake air temperature rises, thermal valve opens, allowing cool air intake door to drop and unheated air into air cleaner.
A thermo wax portion of the hot idle compensator (HIC) valve is located inside the air cleaner. This thermo wax responds to temperature conditions. When it senses a high-heat condition, it opens to allow some air to flow directly from the air cleaner to the intake manifold.