1975-1983 BMW 3 Series repair manual (E21):Air filter
The air filter is a vital piece of any engine. Here is how to remove, install, and inspect one on the 1975-1983 BMW 3 Series (E21)
Removal and Installation[edit | edit source]
6 Cylinder engines[edit | edit source]
The air filter element on all 6 cylinder engines is removed by unsnapping 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.
NOTE: When replacing the square type element used on most later models, always make sure that the airflow arrow direction points toward the engine/into the manifold when installing the filter.
Air filters can be cleaned to some extent by shaking or blowing compressed air through them.
Carbureted Engines[edit | edit source]
The air filter on these engines sits on top of the carburetor. To remove the filter, simply unsnap the housing cover and lift out the filter.
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[edit | edit source]
2002Tii Models[edit | edit source]
The 2002 models utilizes a long cylindrical air cleaner housing with 2 filters in each end. They are 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 filters.
320i and 318i Models[edit | edit source]
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 tube. Next, remove the 2 bolts fastening the vacuum limiting valve and the cold start valve, to the bracket close to the injection pump. Unsnap the over-center catches. While holding the 2 valves out of the way, pull the filter element up and out of the air cleaner housing.