Vacuum Motor Controlled (2.8L & 3.1L)

This system consists of an air cleaner assembly with integral air control door, vacuum control temperature sensor, vacuum motor, heat shroud (on exhaust manifold), heated air tube and vacuum hoses.

• - VACUUM CONTROL TEMPERATURE SENSOR  The vacuum control temperature sensor controls the operation of the air control door. During initial start-up situations, this valve directs engine vacuum to the air control vacuum motor. The motor closes the air intake door, allowing the intake of heated manifold air. When the intake air temperature reaches a pre-calibrated value, this valve opens, allowing the intake of cooler outside air.
• AIR CONTROL DOOR  The air control door temperature sensor closes when the temperature of air entering the air cleaner is less than the calibrated temperature of the temperature sensor. This allows engine vacuum to operate the air control door vacuum motor, and warm manifold air to be routed to the throttle body.
• VACUUM MOTOR  When engine vacuum is applied to the vacuum motor, the air control door stops the intake of outside air. The air cleaner then draws in air from around the exhaust manifold. As air inside the air cleaner warms, the temperature sensor begins to open, bleeding off vacuum to the vacuum motor. As vacuum to vacuum motor decreases, the air control door begins to open. As air control door opens, outside air is allowed to enter air cleaner assembly. When air entering air cleaner reaches a predetermined temperature, the air control door opens completely and stops the intake of heated air.