Thermostatic Air Cleaner: Testing and Inspection

Heated Inlet Air System:

INSPECTION

Ensure all vacuum hoses and the stove to the air cleaner flexible connector are properly installed and in good condition.

COLD ENGINE OPERATION

With engine cold and running, and ambient temperature in the engine compartment below 115°F, the heat control door in the heated air assembly should be in the up (heated air) position.

WARM ENGINE OPERATION

With the engine warmed to operating temperature and running, check the air temperature entering the heated air assembly or at the sensor. When temperature is 140°F or higher the door should be in the down (ambient air) position.

Heated Inlet Air System Components:

SYSTEM TEST

1. Remove air cleaner from engine and allow engine to cool down to 115°F. Using a suitable vacuum pump, apply 20 inches Hg vacuum to the sensor. The door should be in the up (heated air) position. If not, check vacuum diaphragm.
2. 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 inches of vacuum and should be in full up (heat on) position with no more than 4 inches of vacuum. If diaphragm does not operate properly, replace diaphragm.
3. If the diaphragm performs properly but proper temperature is not maintained, replace the sensor and repeat procedure.