How to Replace a Cabin Filter on a BMW 323i

1. Open the hood for a clear view of the engine bay. The cabin filter compartment is at the base of the windshield cowl, directly below the windshield wipers in a long, thin, black compartment about 2 feet wide by 5 inches deep.
2. Locate the three fastener screws in the cabin filter cover; there will be two on the ends and one in the middle of the cover. Turn all three fastener screws counterclockwise one-quarter of a turn to release and remove the cabin filter cover.
3. Remove the cover by lifting it up and pulling it toward the front of the vehicle. The old filter is now visible. Lift the old filter and pull it toward the front of the vehicle to remove it.
4. Ensure the curved shape of the filter matches the curved contour of the windshield before installing the new cabin filter. Hold the filter in the correct orientation and slide it into the filter compartment. Snap the two tabs on the bottom left and bottom right sides of the new filter into the cabin filter compartment slots.
5. Reinstall the filter compartment cover and secure the three fastener screws by pressing them down and turning them clockwise one-quarter of a turn each.
6. Close the car's hood.