I take care of a fleet of off road trucks. I switched a number of them to the K&N, and I actually found tracks where air was passing the filter seal on several vehicles. This was in the grease that was sent with them.
Also, there were heavy dirt deposits in the plenum and throat area of the 6.2 diesels.
That finding, and the hassle of the cleaning and oiling sent me back to NAPA Gold.
I saw absolutely no change in power or performance, and even went so far as to leave the K&N decals on the filter housing after switching to NAPA. Some of the drivers "Marveled" at the "increased power", thinking they were on K&N filters.
I said "It must be the dirt doing the work".
I haven't heard anyone mention that claim in other posts.
I just stick a new NAPA out of the box in about every other oil change, and feel good.
Fix
Also, there were heavy dirt deposits in the plenum and throat area of the 6.2 diesels.
That finding, and the hassle of the cleaning and oiling sent me back to NAPA Gold.
I saw absolutely no change in power or performance, and even went so far as to leave the K&N decals on the filter housing after switching to NAPA. Some of the drivers "Marveled" at the "increased power", thinking they were on K&N filters.
I said "It must be the dirt doing the work".
I haven't heard anyone mention that claim in other posts.
I just stick a new NAPA out of the box in about every other oil change, and feel good.
Fix