Air Cleaner Housing: Description and Operation

Air Cleaner Assembly (20 Valve Engine Up To March 1990):

Air Cleaner Assembly (20 Valve Engine From March 1990):

Small particles of dust and dirt, if allowed to enter the engine with the intake air, can cause severe engine damage over a relatively short period of time. The air cleaner filters out these particles. It consists of a plastic housing (2 piece) that clips together to hold a paper filter element, and directs air to the air mass sensor, which mounts directly to the air cleaner housing.

Air enters the lower housing through a thermostatically controlled air valve that draws hot air from around the exhaust manifold when the engine is cold, and blocks the hot air duct allowing in cool fresh air from in front of the car when the engine is hot.

The filter element is made of a fibrous paper material that, if unfolded and laid flat, has a surface area of several square feet. The filter surface area is this large so that the filter will not significantly restrict air flow (except of course when it's clogged with dirt). Also, the larger the surface area the longer the interval between services.