The heated air intake portion of the air cleaner consists of a bimetal switch and vacuum motor and a spring-loaded temperature control door in the snorkel of the air cleaner. The temperature control door is located between the end of the air cleaner snorkel, which draws in air from the engine compartment, and the duct that carries heated air up from the exhaust manifold. When the temperature under the hood is below 90°F, the control door prevents underhood air from entering the air cleaner, allowing only heated air from the exhaust manifold to be drawn into the air cleaner. When underhood temperatures rise above 130°F, the control door blocks off heated air from the exhaust manifold and allows only cooler air to be drawn into the air cleaner.
By controlling the temperature of the engine intake air this way, exhaust emissions are lowered and fuel economy is improved. In addition, throttle plate icing is reduced and cold weather driveability is improved.
- With the engine cold and underhood temperature below 90°F, check the position of the temperature door in the air cleaner. It should be in the up position, blocking off underhood air.
- Immerse the air cleaner duct assembly in water after removing the air cleaner from the car. Raise the temperature to 130°F and allow the temperature to stabilize for five minutes. The temperature control door should be in the down position, blocking off heated air from the exhaust manifold.
If the temperature door does not react this way, and the door is not binding, replace the duct and valve assembly.
REMOVAL & INSTALLATION
- Disconnect the vacuum hose at the vacuum motor.
- Remove the hex-head cap screws that secure the air intake duct and valve assembly to the air cleaner.
- Remove the duct and valve assembly from the engine.
- Position the duct and valve assembly to the air cleaner and heat stove tube. Install the attaching cap screws.
- Connect the vacuum line at the vacuum motor.
- Label and disconnect the vacuum hoses.
- Remove the clamp securing the switch to the air cleaner.
- Withdrawl the switch from the air cleaner.
- Installation is the reverse of removal.