I have had my K&N Airfilter on my truck for over 1 year and the truck is never driven off -road. My question is ,when do you know when to clean it?

 

over a year... it most likely time to clean. (depends on how much you drive it) just look at the filter... remember that nice nice purply/ red color it had, most likely now its got like a blackish grayishgook all on it, and that means its time to clean. but all in all a year of driving should mean its needs it.

 

Remeber not to use too much oil, or you might screw up you MAF. I put my original filter back in for a couple of days and let the K&N set for a day or two to drain any excess oil off.

 

The filter is black now. I will clean it now. Thank You for the information.

 

hmmm. Doesn't a somewhat dirty filter perform better than a newly cleaned one? I'm sure I read that on here, and even from K&N. I believe 50000 miles is cleaning interval.
I got **** though a few weeks ago and decided to clean mine anyway after 20000 miles. Easy enough to do!

 

I had a K&N FIPK on my 2000 truck and installed an Outerwears pre-filter at the same time. The filter never looked dirty in 4 years. Washing the pre-filter was alot easier.