All the dust present in the air is kept out of the engine by means of the air cleaner filter element. Proper maintenance is vital, as a clogged element not only restricts the airflow and thus the power, but can also cause premature engine wear.
The filter element should be cleaned or replaced every 15,000 miles (24,000 km), or more often if the car is driven in dusty areas. The condition of the element should be checked periodically; if it appears to be overly dirty or clogged, shake it; if this does not help, the element must be replaced.
The paper element should not be cleaned or soaked with gasoline, cleaning solvent or oil.
REMOVAL & INSTALLATION
The air filter on these engines sits on top of the carburetor, usually towards the center of the engine compartment. To remove the filter element, simply unsnap the housing cover and lift out the element.
Clean the element by lightly shaking it against the palm of your hand (blowing with compressed air is also acceptable). If the filter element remains clogged after cleaning, replace it.Fuel Injected Engines
See Figures 1, 2, 3, 4, 5 and 62002Tii MODELS
This model utilizes a long cylindrical air cleaner housing with 2 separate filters in each end; it is located in the left side of the engine compartment. To remove, unsnap each end from the main body of the housing and lift out the filter elements. Clean in the same manner as described for carbureted engines.318i AND 320i MODELS
This model utilizes a square air filter element and housing, located in the left, front side of the engine compartment.
To remove, loosen the clamp connecting the vacuum limiting valve to the air intake duct. Next, remove the 2 bolts fastening this valve and its companion valve, the cold start valve, to the bracket near the injection pump. Unsnap the over-center catches and, while holding the 2 valves out of the way, pull the filter element up and out of the air cleaner housing. Clean in the same manner as described for carbureted engines.
See Figures 1, 2, 3, 4, 5 and 6
The air filter element on all 6-cylinder models is removed in basically the same manner. Unsnap the 2 over-center catches and split the 2 halves of the housing apart. Lift the element upward slightly to separate it from the lower half of the housing and then slide it out of the opening between the 2 halves.
When replacing the square type element used on most later models, always make sure that the arrow indicating airflow direction points toward the engine (or into the manifold) when positioning the filter. Also make sure that the rubber border on the element is properly positioned around the lower case half before closing the catches.
Clean in the same manner as described for carbureted engines.