K&N Maintenance

[rrausch]

I just cleaned and re-oiled my K&N (stock box) Air Filter after 40,000 miles. I think I've got it figured out how to properly clean, oil and re-install the thing. Here's what I did.



First I bought a K&N "recharger kit" for about $7 from Pep Boys.

I removed it from the box and brushed the filter first with a soft-bristled paint brush and it was amazing how much black crud came off it. After I brushed as much off as I could, I sprayed it with the K&N cleaner and let it sit for 10-15 min. , then ran luke-warm (Not Hot) water through it from the clean side, reverse-flushing it. (Hot water will shrink the cotton. ) Also, K&N says any good detergent will work, but of course they "recommend" theirs.



I made sure all the crud was out of the pleats and repeated the cleaning process just to be sure. I then let it sit to dry near a warm air register but again not so that it would get hot--didn't want to shrink the cotton.



When I re-oiled it I used about 1/2 the 6. 5 Oz. spray can. Here K&N is very specific. USE ONLY K&N OIL. Don't use anything else to re-oil it--and NEVER run it dry. When I put it back in the filter box I bedded it into the stock filter box with a little Syl-Glide Silicone grease.



I got a little worried, the next day, that I had used too much red oil, so I e-mailed K&N and was promptly answered by an engineer from the tech dept. He said our Dodge/Cummins (stock box) rectangular filter is charged at the factory with 3. 5 Oz. of oil. So I figure about 1/2 the 6. 5 Oz. can is about perfect.



Drying it takes some time. Just let it sit and dry, don't try to speed things up with a hair dryer or anything.

Although each specific task didn't take much time, 4-5 hours probably elapsed while I did this job--most for drying. Next time I will pull it late in the evening and let it dry overnight.

 

[illflem]

I install a stock paper filter while waiting for my K&N to dry. Keeps me going and really makes me appreciate my K&N.

 

[Diesel Freak]

Originally posted by rrausch



When I re-oiled it I used about 1/2 the 6. 5 Oz. spray can.

OMG... . that is way too much ... one can will do two truck air cleaners, and 3 of the filters for my quad.

 

[rrausch]

Diesel Freak, why do you think 1/2 of the 6. 5 oz. can is too much?

 

[Diesel Freak]

All you need is enough to turn the filter red... .

 

[Diesel Freak]

https://www.turbodieselregister.com/forums/showthread.php?s=&threadid=32336

 

[rrausch]

Well, I sprayed "exterior" side of the filter once, making a light pass on every pleat and then set it aside for almost an hour. After the hour I examined it in strong light and the sprayed side was red while the turbo side was still whitish. A whitish area means there is no oil present. So I sprayed the exterior side again, using a very quick, light pass on every pleat. This by my estimate used a little less than 1/2 of the 6. 5 Oz. can.



I worried that I might have used too much and e-mailed this question to K&N: How can I tell if I oiled the K&N air filter for my 1995 Dodge/Cummins Diesel a little too much? It feels like I used maybe 1/2 of the 6. 5 ounce spray can of red oil. I have the rectangular filter, which fits into the stock filter box.



This is the response I received from Richard Blum, who is a K&N engineer: That's about perfect. This filter takes 3 1/2 oz. of oil when I looked at the Bill of Materials we use to make it...



So I ran the filter 100 miles and checked the clean side of the box and turbo inlet tube... absolutely NO trace of red or oily residue.

 

[baby.driver]

I keep two K&Ns so the clean one goes in the box while I'm cleaning the other. Then when it is dry I store it for next time.

I also spray them very heavy, after all, the oil is what is doing the filtering, the cloth fabric is so the oil and dirt have a place to stay.



Jay