Intake Air Temperature Control System

Testing The Intake Air Temperature Control System:

Using Compressed Air:

SYSTEM TEST

1. Remove the air cleaner cover and air duct.
2. Run the engine at idle.
3. Check the air control valve:
- If the thermo sensor is below 30°C (86°F), the valve will be pulled up allowing warm air from the exhaust heat shroud to enter the air cleaner.
- If the thermo sensor is above 45°C (113°F), the valve will be in a horizontal position allowing fresh air in from the air duct.

Vacuum Motor For Air Control Valve:

AIR CONTROL VALVE

1. Disconnect the vacuum hose from the air control valve.
2. Connect a hand vacuum pump to the valve nipple, apply 19.0 in. vacuum to check air tightness.

Testing The Air Control Valve:

3. Release vacuum and reapply 2.8 in. vacuum.
Cold air inlet side is open.
4. Increase vacuum to 7.5 in.
Cold air inlet side is closed off.
5. Reconnect the vacuum hose to the original position.

Testing The Thermo Sensor:

THERMO SENSOR

1. Connect a hand vacuum pump to the thermo sensor nipple.
2. Apply vacuum.
If the thermo sensor temperature is below 30°C (86°F), vacuum will hold.
If the thermo sensor temperature is above 45°C (113°F), vacuum will leak.

If any fault is found in the above tests, the air cleaner body should be replaced.