Thermostatic Air Cleaner: Testing and Inspection

1. Disconnect ambient air duct and observe position of air diverter valve. It should be fully open to incoming ambient air (heat off position).
2. Start engine and observe position of air diverter valve. It should be fully closed to incoming ambient air (heat on position).
3. Quickly open throttle 1/3 - 3/4 open and release. Air diverter valve should momentarily remain stationary and then move toward heat off position and back to heat on position.
4. Loosely attach flexible ambient air duct and allow engine to reach normal operating temperature. Remove ambient air duct and observe air diverter valve. It should either fully open to ambient air or an in between position that allows correct inlet air temperature. Stop engine and connect air duct.
5. If operation of diverter door is not as outlined, inspect for a mechanical bind in the snorkel, disconnected vacuum hoses or leaking vacuum motor, thermal switch, reverse delay valve and check valve.