K&N Air Filters

[Mudman]

The oil in turbo not a big deal.  Ford diesel ccv coats everything already!  Dirt passing thru filter is a big deal.  I run big donaldson paper filter and it is great!  KN not that great, too much hype and pain in ass to clean properly.  15 dollar paper flows realll goood and last long time.

[BigGoonTuna]

had a K&N in my truck when i bought it, ended up chucking the thing.  a real pain in the butt to clean, and i could buy 3 or 4 paper filters for what 1 K&N costs, and the paper ones last a couple years each.

[Bean Counter]

Old thread now, but I wanted to provide some follow up. I have two vehicles with the same engine that live in the same environment. I run Mobil 1 Synthetic in both engines.  One engine uses a paper air filter and the other has a K&N. I've done several oil changes on both. I have to say that the oil that comes out of the engine with the K&N air filter is markedly cleaner than the paper filter... Just an FYI.. This is a very fair comparison given the two engines and that I don't have a dog in the fight (ie, stock ownership, etc).

I really should check the MAF on the one with the K&N though..

[Mudman]

Im not sure oil is a good indicator of air filter?  Turbo vanes and valves would be more affected.  Dirty oil might mean alot of blow by?

[Bean Counter]

   Just an observation. I'm a poser-jackwagon and by no means a pro. I do my own fluids, spark plugs, and what not and usually stick with the pros for alignments, timing belts, etc.

I usually buy gas from the same places and drive them in the same environment. In fact, the one with the K&N sees more off road time so I would think it should be dirtier. Its also older so I would think the rings would be more worn and let more exhaust into the oil.. Again, 

[Mudman]

You may be correct as im not a pro nothing.   I run Kn filters on toys but not my powerstroke.  My Stepdad is a cert mechanic 30+ years and isnt a kn fan at all.  Or pennzoil.

[tony04]

Im not sure oil is a good indicator of air filter?  Turbo vanes and valves would be more affected.  Dirty oil might mean alot of blow by?

[DoubleJ]

Five thumbs down. They let way too much dirt through

[Bean Counter]

So if the oil quality isn't an indication--how do we know how much dirt they let through?

[Mudman]

   Air flows thru valves to combustion chamber.  Dirt can damage valves and rings which can lead to blow by and same with valves so your oil observation holds water.  Bad valves and rings from dirty air cause poor compression poor running smoke from valve leak etc.  Check the air inlet behind air filter for dirt if you want to know for sure.

[Rick]

So if the oil quality isn't an indication--how do we know how much dirt they let through?

The only way to know for sure is to run a used oil analysis.

Everything else is just a guess.