How to clean K&N filters – Step-by-Step Guide

K&N air filters are one of the most sought-after filters in the market and are available for almost all applications. While people have reservations about it, many still purchase it, particularly for two reasons. First, it allows high airflow into your engine, invariably increasing power, especially for those who modified their engines.

Secondly, you can use it for a long—even throughout your vehicle’s lifetime, saving you cost in the long run.

However, to use it that long, you must clean and reoil it using the K&N air filter cleaning kit—a task requiring utmost care. This article will show you how to clean K&N air filters. But how do you know your K&N filter is even dirty?

how to dry k&n air filter fast
Image Credit: YouTube Screenshot by KNfilters

How can you tell if a K&N is dirty?

One of the many disadvantages of the K&N filter is that it takes a long time cleaning it. And this task many find daunting. So cleaning this filter is not something you wake up one morning to do. Therefore, one needs to be sure they are dirty before taking out time to clean them. So here is how to know when to clean K&N air filter.

How to clean K&N air filter step-by-step guide

Cleaning filters may look simple until it costs you something expensive. To remove dirt from the filter, you must do it a certain way, so you don’t damage the filter. First, you need to wash and then oil the filter afterward.  However, to clean the K&N air filter, you will need their power cleaner, then oil the filter using the K&N filter oil. So here is how to clean K and N air filters without causing damage.

Tools needed

  • K&N recharge and service kit
  • K&N power cleaner
  • K&N filter oil
  • Garden hose

Step 1: Locate and take off the air filter

Your air filter should be close to the top or in front of your vehicle’s engine. If you find it challenging to locate, you may need to look through your owner’s manual. Next is to remove the filter from its housing.

Step 2: Apply the K&N power cleaner

Spray the K&N power cleaner on both sides of the filter and let it sit for 10 minutes. That is, in and outside the filter.  Do not allow the cleaner to dry on the filter, and do not use the sun to dry it.

Step3: Rinse off

Use a garden hose and catch to rinse out the power cleaner. Rinse from inside, then progress to outside the filter till only clean water flows out. You may need to place your fingers on the hose’s tip to ensure you work with low water pressure (avoid pressure washer)

Step 4: Dry the filter

Carefully shake the filter to remove excess water and allow it to dry completely. The drying period takes time, usually around 1-2 hours, making many seek how to dry K&N filter fast. But it’s best you let it dry naturally. Avoid using compressed air.

Step 5: Oil the filter

After washing and you’re sure it’s completely dried, oil it this way. Evenly apply an oil coat to the intake side of the filter using a squeeze bottle or spray can.  Apply the oil evenly on the crown of each pleat if using a squeeze bottle.

If you’re using a spray bottle, ensure the oil is sprayed evenly across the crown with each pleat. Ensure there is a gap of at least three inches between the nozzle spray and the filter. Then let the oil sit for about 20 minutes. Lastly, apply to areas that still look pale on both sides of the filter until there is a uniform red color on all areas of the filter.

Step 6: Look properly

Ensure no excess oil is dripping from the filter. If they are, wipe underneath the filter with a clean rag to remove excess oil.

Step 7: Re-Install the filter

Return the filter to your car’s intake system. Regularly maintaining the K&N filter should provide free airflow and efficient air filtration for your vehicle for many years.

cleaning k&n air filter with dish soap
Image Credit: YouTube Screen Short by Home Built Workshop

How do you clean K&N filters without a kit?

K&N requires you to use the K and N filter cleaning kit when cleaning the K&N filter to ensure all go smoothly. However, getting this kit is an additional cost on its own which many try avoiding—K&N products are generally more expensive than other regular products.

So you can alternatively opt for a cheaper cleaner and oil. But understand that anything that goes wrong is on you, especially with the oil. With that in mind, let’s see how to clean  K&N filter without kit.

Tools Needed

  • ATF super cleaner or other cleaners like the WD-40 degreaser
  • ATF automatic transmission fluid (it has the same property as the K&N oil) or other light-grade oil like the WD-40
  • Syringe (without the needle)
  • Paintbrush


  • Remove dust using a quality paintbrush
  • Spray the ATF super cleaner (or your chosen car air filter cleaner)  generously on the fitter and allow it to sit for about 10 minutes
  • Wash the filter from inside out with a hose, preferably with warm water and low pressure
  • This might not give you that shiny look. So spray again and rinse with warm water until clean water starts coming out.
  • Allow it to dry quite naturally, don’t be tempted to use compressed air. Allow it to dry naturally.
  • To oil, suck some oil into a syringe (without the needle). Ensure the oil is a light-grade oil; you can know this by first spraying the oil on a 6-inch paper.
  • Lay the oil carefully across every fin (this may take a longer time, but it sure works)
  • Retouch areas that still look pale. You should have a uniform red look on the filter after you finish oiling.
  • Ensure no oil is dripping from the filter. If it is, cleans it off.
  • Allow it dry
  • Reinstall the filter into your car’s intake


Q: Can you use dish soap to clean a K&N air filter?

Yes, you can clean a K&N air filter with dish soap. However, whatever dish soap you use must be mild; K&N filters have no issues using mild degreasers on their filters. A good example of mild dish soap is the dawn dish detergent.

If it can be used to bathe your ducklings, it should be subtle for your K&N air filter. Cleaning k&N air filter with simple green could also be an alternative. But the catch here is that your dish soap might not clean as efficiently as the K&N power cleaner. This is why it is always advisable to use the K&N cleaning kit.

However, if you still want to use dish soap, you may spend longer as you may need to repeat the process twice to have a clean filter. That is degreasing, rinsing out, degreasing again, and rinsing out. So for those asking, can I clean my K&N air filter with soap and water? Now you know.

Q: How often do K&N filter need to be cleaned?

You can clean the filters once yearly, or every 25k miles. If, however, you regularly drive in a very dusty environment, you may need to check more often. Or alternatively, clean depending on the filter’s condition.

If your cabin air filter starts blowing smelly air, it might be time to clean it. In the same vein, if your car starts losing power, lugs, or consumes more fuel, check your fuel pump and filters. Physical dirt on them, especially when you no longer see the wire mesh, indicates they are due for a cleaning.

Q: Can you use WD-40 on K&N air filter

K&N oil is designed specially for its filters to efficiently trap dirt to prevent engine contamination and oil from fouling the MAF. So while you can use the WD-40, it may not be able to filter germs efficiently like the real K&N filter oil.

And if you’re not careful enough, you may use a heavy oil grade unsuitable for the filter. This can ultimately foul the MAF sensors.

Q: Can you use a brake cleaner to clean a K&N air filter?

No, you can’t. K&N filters have warned users never to use a brake cleaner on the K&N air filters. According to the manufacturers, a brake cleaner can damage the cotton gauze material used on the filter. Therefore, choosing to do it means nullifying the purpose you opt for it in the first place—using it for long.

Q: Do K&N filter damage the engine.

There are controversies as to whether K&N filter damages the engine or not. Generally, K&N filters use a wider filtration media that allows a high flow of oil, air, or fuel. However, this also means dirt will find its way through since the filter media is wide.

This is why K&N uses oil on its filters to trap contaminants that might enter your car or engine. However, people still complain that even with the oil, dirt still passes through to the engine or car. And even worse, when the filter is under-oiled. With this going on for long, your engine is susceptible to damage.

Q: Do you need to oil K&N air filter?

Yes, it is a must to oil the K&N air filter, as the oil is what traps the contaminant. Without the oil, the rate at which dirt enters the engine or cabin will be so high that, in a short time, your engine may get damaged. Or bad air will start entering your cabin.

However, when oiling, you need to be extremely careful. Putting too little oil reduces the filter’s filtration capacity causing dirt to enter the engine at a high rate.  On the other hand, if you put too much oil, the oil can leak out and contaminate the mass airflow sensor, causing unnecessary replacement.

Q: Do you oil both sides of a K&N air filter?

You oil only the outside of the filter. The oil will eventually soak in. So if you mean both sides outside the filter, yes, you should oil both sides. But if you mean both sides, that is, inside and outside the cone, no. You don’t apply or spray oil inside the cone. Just hold the filter and oil it round from the outside.

Q: What oil do you use on a K&N air filter?

K&N filters have special oil formulated for their filters—whether air, fuel, or oil filter. This oil has the perfect properties to trap dirt without damaging the filter. So while people tend to use other oil, the right type of oil to use on K&N air filters is the K&N filter oil.

Q: How often should I oil my K&N air filter

You are required to oil the K&N filter every time you clean it. Wondering how often to clean K&N air filter? This should be once yearly or anytime it gets visibility dirty. Understand that the filter will get dirty faster if you regularly commute on dirty or dusty roads.


By now, you must have known how to clean K&N filters effortlessly. Remember, it’s recommended to use the K&N cleaning kit and filter oil to ensure everything goes smoothly. If, however, you choose to do it without the cleaning kit, be very careful and understand that whatever happens is on you. This job is also time-consuming.

So this brings to mind, how long does it take to clean K&N air filter? Practically between 2-4hours, depending on your approach. This includes the cleaning and drying period. This is why you must ensure your filter is dirty before taking on such a task that seeps your time. To know if it’s dirty, check for visible dirt on the filter or clean once yearly or every 25k miles. Alternatively, clean as instructed by K&N.

Osuagwu Solomon

Osuagwu Solomon is a certified mechanic with over a decade of experience in the mechanic garage, and he has over five years of experience in the writing industry. He started writing automotive articles to share his garage experience with car enthusiasts and armature mechanics. If he is not in the garage fixing challenging mechanical problems, he is writing automotive repair guides, buyer’s guides, and car and tools comparisons.

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