The air filter is critical to maintaining a healthy engine, allowing clean air into your engine to combine with fuel, combust and produce the vehicle's power. Over time, accumulation of dirt, dust, pebbles and more can impede this airflow. If your filter is dirty, your engine will need to work harder to draw in air or cool down. Eventually, those unwanted materials can be sucked into your engine from the air intake while on the road, potentially damaging the pistons and blocking your carburetor.
There are two different classes of air filters: oiled and dry. Typical dry air filters are made of foam, which blocks more particulates than paper filters, but due to their material density they've been known to inhibit air flow as they get dirty. These types of oiled filters should be cleaned or replaced about every 15,000 miles, or more frequently if you live on dusty roads or in more polluted areas.
K&N® air filters are also popular, particularly on motorcycles and all-terrain vehicles. These filters use an oiled cotton gauze construction. A thorough cleaning of these is only required when portions of the screen are no longer visible in the filter, or roughly every 50,000 miles.
When cleaning your air filter, it's important to use a cleaner that will thoroughly remove dirt and debris without petroleum-based chemicals, which can damage or dissolve the filter materials. You should avoid using solvents or kerosene for this reason.
Simple Green All-Purpose Cleaner is aggressive on grease and heavy soils, but is gentle enough to clean air filters without harming the filter material or causing damage to surfaces found on automotive equipment. When used per label instructions, it's safe on aluminum, chrome, titanium and other high-tech alloys, as well as painted and gel-coated surfaces, anodized and electroplated parts, carbon fiber, metals, plastics, rubber and much more.
Check your Owner's Manual before cleaning the air filter. Always follow manufacturer's complete instructions for cleaning and maintenance. Make sure the engine is cool to the touch before cleaning.
- Remove air filter. Take the air filter out, taking care to make sure no dirt or debris falls into the air box or intake. If there's any housing on the filter, remove the housing and the wing nut attaching the filter to remove the outer element.
- Apply cleaner. Spray the entire surface of the filter with Simple Green All-Purpose Cleaner, allowing the cleaner to soak into the filter.
- Rinse. Using a faucet or garden hose, rinse the filter from both sides, starting from the interior towards the exterior to prevent pushing dirt further into the fibers of the filter. Avoid wringing or stretching the filter – they can tear easily. Rinse until the water runs clean. Repeat process if necessary.
- Dry. Shake any loose water from the filter, then set it down to air dry. Make sure filter is completely dry before oiling (if you have an oiled filter) and replacing.
- Oil and replace. If you have an oiled filter, follow this step. Use fresh filter oil to saturate the entire filter, including the sealing flange and lip. Modern vehicles that use a Mass Air Flow (MAF) sensor require special care when re-oiling these types of filters, to avoid over-oiling and affecting sensitive wires of the MAF. This could cause it to incorrectly measure air consumption, resulting in a “check engine” light. Spray the oil evenly along the crown of each pleat on the filter. Then squeeze out the excess and return the filter to its housing.