Thermostatic Air Cleaner: Testing and Inspection

SYSTEM TEST

To test this system use the following steps:
1. Ensure all vacuum hoses and the stove to the air cleaner flexible connector are properly installed and in good condition.
2. With engine cold and running, and ambient temperature in the engine compartment below 100°F, the heat control door in the snorkel should be in the up (heat on) position.
3. With the engine warmed to operating temperature and running, check the air temperature entering the snorkel or at the sensor. When temperature is 130°F or higher the door should be in the down (heat off) position.

Heated Inlet Air System Test:

4. Remove air cleaner from engine and allow engine to cool down to 110°F. Using a suitable vacuum pump, apply 20 inches Hg vacuum to the sensor. The door should be in the up (heat on) position. If not, check vacuum diaphragm.
5. To test the vacuum diaphragm, apply 20 inches of vacuum with a vacuum pump. The diaphragm should not bleed off more than 10 inches of vacuum in 5 minutes. The door should not lift off the bottom of the snorkel at less than 2.5 inches of vacuum and should be in full up (heat on) position with no more than 5.5 inches of vacuum. If diaphragm does not operate properly, replace diaphragm.
6. If the diaphragm performs properly but proper temperature is not maintained, replace the sensor and repeat procedure.