4. How often do I need to clean my K&N air filter?

If you have not experienced a decrease in mileage or engine performance, chances are your filter is fine and does not yet need cleaning. To be more specific, the filter does not require cleaning if you can still see the wire screen on the entire air filter regardless of how dirty it may appear. When the screen is no longer visible some place on the filter, it is time to clean it. When used in normal paved road, street or highway conditions, our replacement air filters that fit in the factory air box should require cleaning every 50,000 miles and our large conical filters on an intake system should require cleaning every 100,000 miles. When used in dusty or off-road environments, our filters will require cleaning more often. We recommend that you visually inspect your filter once every 25,000 miles to determine if the screen is still visible.

27. Will a K&N filter cause my vehicle's mass air sensor to fail?

No, it is both impossible and ridiculous.

It is impossible because we know that the oil treatment on our cotton is very small (usually less than 2 ounces). Once the oil is properly and evenly absorbed through the cotton, no oil will come off, even under extreme engine conditions. It is ridiculous, because no dealership or service provider has ever been able to provide us with evidence to support this "myth," and in fact, our investigations have revealed that even authorized dealerships are simply speculating and do not have the test equipment necessary to know whether the sensor has failed or why. It is even more ridiculous because some car manufacturers use and sell air filters treated with oil on a regular basis. There are also major brands of disposable air filters that are treated with oil. We all use oil for the same reason, it helps in the filtration efficiency of an air filter. For more information on this topic including videos, see our Mass Air Flow Sensor Statement page.

Out of the millions of air filters we sell, we only receive a handful of consumer complaints each month that a dealership or service provider has blamed a vehicle sensor repair on our product. We take each complaint very seriously and see it as an opportunity to stop a consumer from being taken advantage of. We investigate the situation thoroughly and take full responsibility for resolving the issue. For more information on how we educate and persuade the service provider to reconsider their position, see Mass Air Flow Sensor Information & Testing. We are so confident in our ability to resolve these situations and to help a consumer fight back that we offer our Consumer Protection Pledge.

As a result of our standing up for consumer rights and providing assistance to resolve a disagreement, we have had over 100 actual sensors sent to us by dealerships who claimed our product had caused them to fail. Microscopic, electronic and chemical testing revealed that none of the sensors were contaminated by K&N oil (K&N Detailed MAF Sensor Test Results). What is perhaps the single biggest clue to what is going on is that over 50% of these sensors were not broken in the first place for any reason. Click here for more information on how this may happen.

28. Can a K&N product cause my Check Engine Light or Service Light to come on?

A properly installed K&N product should not cause the Service Light to illuminate. For more information see our Engine Service Lights and K&N Products page.

17. How much oil should I use to re-oil my filter after it is cleaned?

The best way to ensure proper oiling is to use our squeeze bottle recharger kit (Part No. 99-5050). With a squeeze bottle, you simply run a bead along the top of each pleat on both sides of the filter. If using an aerosol recharger kit (Part No. 99-5000), make one light pass over the entire filter area front and back. The oil will then be evenly absorbed throughout the rest of the cotton medium over the next several minutes. We recommend you let your filter set for 1 hour to let any excess oil run off the filter. In any event, you do not need to worry about over oiling your filter and you should make sure the oil appears fully absorbed before re-installation. If you want exact oiling requirements, enter the part number in the "Search by Part" box on our Application Search Page and the factory oil amount will be shown.