How To Clean Your K&N Air Filter
If you love your car or truck enough to have upgraded to either a K&N million mile air filter or a K&N cold air intake kit, you should take the time to recharge the filter every now and then. The good news is that it is easy to accomplish and relatively cheap (MSRP $14).
The K&N website recommends recharging their basic drop-in filters every 50,000 miles, and their cone-shaped filters every 100,000 miles. Of course, this is assuming you drive all those miles on paved roads and in fairly clean air. So if you work in a dusty environment, live on/by a gravel road, or live out in the country by fields you'll need to at least check your filter more often. I generally try to check my air filter every time I change the motor oil, it's a good habit to have.
Below, I have listed the steps to recharging your K&N air filter as well as inserted a few pics to help along the way, which you probably won't need. The steps in this hub will work for all types of long-life air filters not just K&N's (i.e. Volant, AEM, Brute, etc.) You also don't necessarily have to use the K&N Recharger kit. Your local auto parts store will have alternatives, but they all work in the same manner.
The next step is to liberally apply the K&N Air Filter Cleaner to both the inside and outside of the filter. Ideally, you will want to do this outside or in a well ventilated area because the fumes can be strong. I chose to do this in the kitchen sink because my wife wasn't at home to yell at me and tell me not to.
Let the cleaner sit for 10 minutes to break up the grime.
DISCLAIMER: If you are married and you choose to do this in your kitchen sink, you are taking your life in your own hands. I will not be held responsible for what your wife does to you when she finds out.
After the filter has sit for 10 minutes (DO NOT allow the Air Filter Cleaner to completely dry!) use a low pressure water hose (or you kitchen faucet), to clean off the cleaner as well as the dust, grime, bugs, etc. Position the water source so that it rinses from the clean side out.
Continue to rinse until all signs of the air filter cleaner is gone.
Repeat steps 3 &4.
Depending on how dirty your filter is, you may be able to skip this step. I generally do it twice any way simply because two is better than one.
After you've completed washing and have thoroughly rinsed your filter, let it sit to the side until it dries.
I generally sit it out in the sun to speed it up. This Tennessee heat I live with usually dries it up within 30-40 minutes. Be sure it is completely dry before you precede to step 7.
After the filter is completely dried, you're ready to apply the K&N Air Filter Oil. (If you're doing this in your house, use an old large towel underneath to absorb the overspray)
Spray the oil evenly along the crown of each filter pleat. Allow the oil to dry for about 20 minutes then go back over any spots you missed, i.e. that aren't as red as the rest. The filter should be an even shade of red after you're finished.
Now reinstall the filter back into your vehicle. You're finished! Enjoy all that lost horsepower you've gained back from a clean filter.