Review on Engine Filter Washable Reusable 0644 by Chuck Shapiro

I'm getting 1-1.5mpg extra in my 17 Diesel F250! It appears to be about an eighth to a quarter of an inch taller, making it difficult to snap the air cleaner cover into place, but with a little maneuvering it can be done! Read comments elsewhere blaming K&N and all oil-soaked air filters. One of the complaints was that the oil was contaminating the (mass air flow sensor) MAS. #1 If you have this problem, you are putting too much oil on the filter WAAAAAY (after cleaning)! RTFM (Read the Flip manual) #2 They come pre-lubricated with oil. I've been using K&N air filters on my cars (and trucks) for over 12 years and have never had a problem.