Air Cleaner - Thermostatic: Testing

1. Ensure all hoses are in good condition. With engine cold, heat control door in air cleaner snorkel should be down. With engine running at normal operating temperature, door should be up.
2. Turn off engine. Remove air cleaner and allow air cleaner to cool to 50°F (10°C). Using external vacuum source, apply 20 in. Hg (15 in. Hg on 2.6L) vacuum to temperature sensor. Door should be in up position. If not, check vacuum diaphragm for proper operation.
   Fig 1: Thermostatic Air Cleaner

   Courtesy of CHRYSLER MOTORS.
3. Apply 20 in. Hg vacuum to diaphragm. Diaphragm should not bleed down more than 10 in. Hg in 5 minutes. Door should not lift off bottom at less than 5.5 in. Hg. It should be in full up position at no more than 8.5 in. Hg. If vacuum diaphragm does not operate properly, replace it and repeat test. If diaphragm is okay but proper temperature is not maintained, replace temperature sensor and repeat test.

Fig 2: Heated Air Inlet System (2.5L) Other Throttle Body Injection (TBI) models are similar. Courtesy of Chrysler Motors.