How to Clean a K&N Air Filter

A guide to keeping your K&N filter in good condition

Co-authored by wikiHow Staff

Last Updated: May 24, 2022 References

K&N auto air filters are prized for their durable construction and long lifespan. Unlike normal paper filters, they can be cleaned and reused for tens of thousands of miles, which will spare you the inconvenience of having to have your air filter replaced regularly. Best of all, they’re a cinch to clean. Using the Recharger kit included with your K&N filter, just spray the filter with the cleaning solution, rinse it and apply a new coat of dust-trapping oil. Keeping your K&N air filter clean and in good condition will greatly improve your vehicle’s mileage and overall performance.

Part 1

Part 1 of 3:

Cleaning the Filter

1
Remove the filter. Pop the hood on your vehicle to access the engine compartment. Find your air filter—these are almost always housed inside a large plastic box that makes them easily identifiable. If there are ring clamps or latches holding the filter in place, disengage them and lift the filter straight out.^{[1]
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- Depending on the make and model of your vehicle, the air filter may be flat, circular or conical in shape. The methods used to clean the filter will be the same regardless of its design.^{[2]
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- You may also want to stick a towel or some other object into the air intake port to keep debris from entering the engine after the filter has been removed.
2
Determine whether your filter needs cleaning. K&N advises that their air filters only require service if any of the filter’s folds are covered so thickly with dust or dirt that they’re no longer visible. If you can still plainly see the pleats on your filter, it may not need to be cleaned, even if it appears dirty.^{[3]
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- If your filter looks clogged or fuzzy, or if it's lost all traces of its reddish oil coat, it’s probably due for a cleaning.
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3
Shake off loose dust and dirt. Give the filter a gentle shake to dislodge whatever debris is resting on the surface. Don eye protection and a breathing mask if you have them to avoid inhaling dust particles. Be careful not to shake the filter too hard or handle the pleats directly, as this could potentially damage them.^{[4]
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- You can also use a soft-bristled brush to remove dust without harming the filter.
- To avoid making a mess, it’s recommended that you remove your air filter outside.
4
Spray the filter with cleaning solution. Grab the bottle of aerosol cleaner that came included with your filter. Spray the filter liberally on both sides. It’s important that you clean both the inner and outer surfaces of the filter, not just the dirty exterior pleats. Make sure each individual pleat has been thoroughly misted with cleaner.^{[5]
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- Use as much solution as you need to completely coat both sides of the filter.
- K&N's proprietary air filter cleaning solution can be purchased online or wherever auto accessories are sold.
5
Allow the solution to soak on the filter for 10 minutes. As the cleaner sits on the filter, it will begin to cut through caked-on grime, making it easy to rinse away. Place the filter in the sink or on a towel while the cleaning solution does its job. This will prevent dissolved gunk from running off and staining your work surface.^{[6]
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- Be careful not to let the cleaning solution dry on the filter.

Part 2

Part 2 of 3:

Rinsing and Drying the Filter

1
Rinse the filter from the inside out with cool water. Turn on a hose or tap to a light stream. Hold the air filter directly under the stream so that the water runs through the inside of the filter to the outside. The water will carry away the dust and dirt loosened by the cleaning solution.^{[7]
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- Rinsing from the outside in will just force dirt further into the filter.^{[8]
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- If your air filter happens to be especially filthy, you may need to repeat the cleaning and rinsing process more than once in order to restore it to a like-new condition.
2
Shake off the excess water. Alternatively, you can rest the filter against another object at an angle and let it drip-dry. Get off as much standing moisture as you can. Again, try not to handle the filter too roughly.^{[9]
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- Set the filter on a clean, dry towel to absorb more water.
- For quicker drying, make sure you leave the filter in a well-ventilated area at a mild temperature.^{[10]
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3
Let the filter air dry overnight. It will usually take somewhere between six and eight hours for the filter to dry completely indoors. Plan on servicing your air filter at a time that you know you won’t need to drive anywhere.^{[11]
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- Do not attempt to apply oil while the filter is still wet.^{[12]
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- If need be, you can temporarily install a regular disposable air filter so that you'll be able to use your vehicle while your K&N filter finishes drying.

Part 3

Part 3 of 3:

Oiling the Filter

1
Apply a thin coat of oil to each fold in the filter. Your K&N air filter Recharger kit should also include a separate oil in either a squeeze bottle or aerosolized spray can. This oil needs to be spread directly over each pleat in the filter. If you’re using a squeeze bottle, run the tip along the top of the pleat as you squeeze. If you’re using a spray can, hold the filter a few inches away from the nozzle to ensure that the oil coats properly.^{[13]
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- K&N air filter oil contains a subtle red dye that makes it easy to see how much of the filter you’ve covered. By the time you’re finished, the entire filter should have a reddish tint to it.
- Use a paper towel to wipe away excess oil around the edges of the filter and work the oil more evenly into the pleats.^{[14]
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- Be sure to work outside or in another well-ventilated area and spray the oil away from your face.
2
Let the oil stand for 20 minutes. The oil will wick into the surface of the filter, creating a more effective barrier.^{[15]
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- Oil is used to help the filter collect dust, dirt and other debris as it enters the air intake.
- The oil also serves to protect the filter from deterioration, extending its lifespan.
3
Replace the air filter. Slide the filter back into its specified slot in the engine compartment. Remember to reattach any clips or clamps that secure it. Your car’s engine will now be protected, optimized and ready for up to another 50,000 miles of open road!^{[16]
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- Even though K&N air filters are designed to last, you should still get in the habit of checking the condition of your filter every 25,000 miles.^{[17]
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- If you placed a stopper in your air intake, don’t forget to remove it before reinstalling your filter.

Community Q&A

Question

In a pinch, what type of oil can be used for a K&N air filter?

Community Answer

Transmission fluid or power steering fluid works just as well. Just make sure all excess has been drained away. Oil filters can affect your mass air flow sensor if not properly oiled, so it's very important to get all that dripping oil off.
Question

If I spray K&N oil on a standard paper element air filter, will that work until it gets too dirty?

Community Answer

Do not do this. K&N filters use a cotton filter element, and the oil is designed to increase the efficiency of that medium. Applying oil to a paper element will cause the paper filter to have reduced efficiency, as well as weakening the element and thus increasing the risk of it tearing or breaking, similar to a piece of paper towel or toilet paper losing strength when it gets wet.
Question

I have a 2004 Blazer with a rectangular air filter. Do I spray the oil on the filter on both sides - top and bottom - or just one side?

Aherrera505

Community Answer

After properly washing the filter, you want to spray just one side, according to their maintenance tips, but honestly I don't see any harm in putting it on the other side too, as long as you let it dry properly before installing it and starting the vehicle.

Warnings

Never use other means, such as a blow dryer, microwave or oven, to try to cut down on how long it takes the filter to dry. This is guaranteed to ruin your filter.

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Be careful not to over-oil your filter. Excess oil could get sucked into the air intake, triggering your “check engine” light and hindering your engine’s performance.

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