Thermostatic Air Cleaner: Description and Operation

Fig. 32 Thermostatically controlled air cleaner & air control actuator operation:

This system, consisting of an air control actuator and a thermo-sensor, Fig. 32, controls the temperature of the intake air by mixing preheated air and cool air to improve fuel vaporization and engine warm-up operation. The thermo-sensor senses the inside temperature of the air cleaner and regulates the vacuum applied to the air control actuator, thus controlling the damper position, Fig. 32.




Testing

THERMOSTATICALLY CONTROLLED AIR CLEANER (TCAC) SYSTEM
1. Check vacuum hoses for proper installation, deterioration, or damage. Replace as necessary.
2. With air cleaner cool, disconnect warm air hose from warm air duct.
3. Reach into warm air duct to check that damper is closed with engine off.
4. Start engine and run at idle. Damper should open warm air duct.

AIR CONTROL ACTUATOR
1. Disconnect vacuum hose from ACA.
2. Using suitable vacuum pump, apply 7.87 inches Hg (200 mm Hg) of vacuum to ACA.
3. Damper should open fully and remain open with vacuum applied.

Fig. 33 Testing thermo-sensor:

THERMO SENSOR
1. Remove air cleaner.
2. Disconnect 2 vacuum hoses from thermo-sensor.
3. Measure temperature around thermo-sensor.
4. Cover long nozzle with finger and blow air into short nozzle, Fig. 33. Valve should be open at temperatures above 104°F and closed at temperatures below 77°F.
5. After testing, reconnect vacuum hoses and reinstall air cleaner.