brewer13

There is talk about only using dry element air filters on a turbo diesel.

Is that really true? What is the problem with K & N type filters that you can wash and use again?

Are they really that damaging?

gorms

I don't think there is any problem with a re-usable filter, as long as you treat it properly after a proper cleaning. I had a bhaf for a while, then it got wet (really deep puddle ha) so I switched back to the K/N drop in. Haven't had any problems, I was curious if it really does filter everything out so a simple test was to put a small coat of grease in the intake elbow, then checked it with a rubber glove a few months later. I don't drive in dusty areas every day, but a few times a week and it was clean when I checked it. Not sure of the micron level when it's visible though.

Either way, no problems after about 80k on the filter. I've been using filters that need oil for years in my dirtbikes, so I figured it might work ok. BUT, if you don't run it with the right oil I'd say you might as well run without it at all.

Diesel Dave2

I have k&N filters on two cars...I use the K&N re-charge oil they recommend..

infidel

The only problem with wet filters is people not reading or following the service instructions. They over oil, use the wrong oil and over service.

There's no one in the world who can tell if an airfilter is clogged by looking at it, opening the filter box to peek is counterproductive, use the filter minder.

I have a cone K&N on my 3500, the 2500 has a drop in, over 300k miles on each of them with low oil analysis silicon levels.
I service my K&Ns every 100k miles as per the instructions.

joem

I may get flamed for saying this, its just my 0.02 and yes this is extreme conditions that most CTD owners will never ever see....so here it goes... im a huge ATV and dirt bike guy since age 10 (im 37 now) and i have made quite the hobby out of rebuilding the top end of bikes and quads that come from the dunes that had a K&N or similar filter, I have found sand in the entire intake almost every time! hold a k&N up to the sun- you can see light threw it! The first thing I did when I found a K&N under the hood of my used CTD was put it on e-bay and I put a paper back in- truck makes the same boost with the paper as it did with the thin K&N.
For my bikes and quads I use thick dual stage uni-filter foam oil bath filter with a grease grove where it seals to the air box and use super tacky PJ1 spray on super tack foam filter oil. Everything I have owned has never needed a rebuild as of yet, not even my 2 smokes. The first thing I learned in motorcycle tech was that the #1 reason for top end failure or oil burning is dust getting past the airfilter. I apply that logic to everything I own, even my 2 stage air compressor in the shop!

joem

Here is a thread over at the 2 wheel side of my life:
http://www.thumpertalk.com/topic/937672-kn-air-filters/

chariotdriver

I always figured intercooled/waste-gated applications wouldn't get much use out of a high flow/cold air cleaner. The engine gets a little cooler air going into the turbo which jacks up the temp to 250 degrees versus 255 for the hotter stuff under the hood. You make your money on the charge air cooler/intercooler dropping things down into the mid 100 degree range. When your foot is into it the turbo is blowing all kinds of air then the waste gate kicks in and limits how much air the turbo can stuff. My stock stuff tops out around 21......the not stock stuff goes into the 30's; but they both have a point where the waste-gate opens then they peak. The stock air filter is a very good piece of equipment.

ntsqd

I had a K&N style oil-wetted cotton-gauze air filter on my dune buggy. Never, ever opened up the filter to find it clean of grit on the inside. Did not matter what I did or what oil I used. There was always grit on the inside.
My '96 came with a drop-in K&N. It's sitting out back, I replaced it with a real filter.