How to Clean & Re-Oil K&N Air Filter?

One of the many benefits of K& N air filters is that they are washable and reusable. We suggest you should inspect your filter annually or more ofter if you drive in dusty or dirty environments.

One of the most asked questions is how to clean and re-oil the filter.  Of course instructions do come with the filters, but sometimes it helps to go over some of the fine points, so here we go with your most asked questions and our answers.

How do I clean my filter?

Step 1: Carefully remove the air filter from the stock air box or from the end of the intake system.

Step 2: Spray both side of the filter with K&N cleaner. ONLY USE K&N 99-5000 Cleaning Kit.  It is very inexpensive and the only product guaranteed to properly clean your K&N filter and not damage the cotton fibers. It is cheap enough that there is no excuse for using anything else.  I like that K&N makes their cleaning/re-oiling kits very affordable, they don’t try to make these products a profit center.

Step 3: After soaking the element, let it sit for about 10 minutes.

Step 4: Then use a gentle stream of water from the back side (opposite of air flow) to rinse it out. NEVER use high pressure AIR or WATER. I use the kitchen sink most of the time. Most hoses for car washing have way too much pressure, turn down the pressure to a gentle stream.

Step 5: Shake the filter to remove excess water and set aside to dry naturally. I clean my filters either in the evening so they can dry overnight, or when I start a day-long detail session. When the next day dawns or the detail is over, the filter is ready to oil.

DO NOT use compressed air or heating elements to speed the drying process.

K&N Air Filter Cleaning Kit: Aerosol Filter Cleaner and Oil Kit; Restores Engine Air Filter Performance; Service Kit-99-5000

K&N 99-5000 Cleaning Kit

How do I oil my K&N filter?

K&N Air Filter Oil: 8 Oz Squeeze Bottle; Restore Engine Air Filter Performance and Efficiency, 99-0533

K&N Air Filter Oil 99-0533

K&N oil comes two ways, a squeeze bottle of oil or a spray can. Remember you are oiling the OUTSIDE of the filter, the way air goes into the filter.

With the squeeze bottle:

Put one thin line of oil on each pleat, only on one side please.

With the spray oil:

Step 1: Hold the can two -three inches from the filter and spray across the top of one pleat onto the side of the next pleat and put one quick line of oil on each pleat.

NOTE that the spray oil comes out in a sputtering stream rather than a fan spray, like paint.

Step 2: Wait at least 10 minutes and touch up any spots that are still white.The entire filter should have a light red color. 

DO NOT OIL THE ENTIRE FILTER TWICE! Only touch up white spots.

I like to take a lint-free cloth or one of those Scott blue shop towel (paper towels) and lightly pat the filter and wipe off the seal area.  Some drops of oil can stay on the wire mesh, and you don’t really need this oil to be there.   Again, take extra care to never wipe on or pull at the cotton filter material.

Step 3: Reinstall the air filter back into your car.

You done!

K&N Air Filter Cleaning Kit: Aerosol Filter Cleaner and Oil Kit; Restores Engine Air Filter Performance; Service Kit-99-5000

K&N 99-5000 Cleaning Kit

K&N Air Filter Oil: 8 Oz Squeeze Bottle; Restore Engine Air Filter Performance and Efficiency, 99-0533

K&N Air Filter Oil 99-0533

K&N Premium Oil Filter: Designed to Protect your Engine: Fits Select BUICK/CADILLAC/CHEVROLET/FORD Vehicle Models (See Product Description for Full List of Compatible Vehicles), PS-2011
Visit the K&N Store

K&N Premium Oil Filter PS-2011

FAQs

How long will the K&N filter last?

K&N has a “Million Mile Warranty” or basically for the life of your vehicle.  K&N says their filter will go up to 40,000 or more miles before needing cleaning.  They also says that you should not clean your filter more than 25 times or the cotton filter media can become to worn to filter effectively.  If you divide 1,000,000 by 40,000, you get 25….works out pretty nice doesn’t it!

How do I know when to clean my filter?

The best way is to use an air restriction gauge like most bigger diesel trucks have. But without this, you can pretty much see if the filter is getting plugged up. The old drop light held behind the filter is NOT a very good test, but for sure, if you can’t see light through your filter, it should be cleaned.

I recommend to my customers that they clean and re-oil at least once a year, or check it every 30,000 miles. If you drive on a lot of dirt roads, or race on dirt, then you may be cleaning your filter much more often. In that case, consider a K&N “Precharger” filter wrap to keep out the biggest dirt chunks and cut down on how often you have to clean.

What about manufacturer’s claims that the warranty is void?

K&N says that this is not legal. Manufacturers cannot void your warranty for using a K&N filter. The only possible problem comes when a K&N filter is over oiled. Some of the excess oil can get in the air stream and contaminate the MAF sensor or other sensors downstream.

This is a much worse problem with oiled foam filters than oiled gauze. Foam can hold much more oil and it can seep out for weeks or months. A properly oiled K&N filter has never harmed any sensors or caused any problems according to K&N.

I bought a K&N style filter… is it as good?  Is it serviced in the same way?

There are at least two companies that provide a K&N “style” filter. I think that they are probably of good quality, but I don’t think these companies provide the exact fit replacement filters  for factory air boxes. Instead they offer generic filters for aftermarket applications or maybe a few of the most popular vehicles. You should follow the manufacturer’s instructions for cleaning, oiling and service life if you have one of these filters. As a rule, though, they can use the K&N oil and cleaner to maintain them. And what applies to K&N applies to K&N “style” filters.

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