notw

I was reading in another post where several guys said that K&N engine air filters are junk. I have never heard this before and have been running one for over 150,000 miles. Is there another company that makes a good drop-in high flow filter or will I have to spend the $ for a complete intake kit?
Thanks.

tmills

AFE and Amsoil both have drop in filters that work great. I'm not sure that K & N is bad if you oil them correctly (Not to much, but not to little). If you've had yours for 150k, I'd say you'll be alright.

infidel

Don't you think K&N would be out of business if their filters ruined any engines?

I've had one on both my rigs, each with about 300k miles. Bought them at Cummins Northwest.
Regular oil analysis has come back great.
White rag wipe in the turbo inlet comes up clean.

Folks like to point out that if you hold a K&N up to the light you can see pinpoint holes all over the place. What they fail to see is if you looked at it under magnification you would see the holes are criss-crossed with hundreds of tiny hairs.

They don't work well if over oiled or over serviced but that's just a failure of the owners to follow directions.
I only service my K&N every 100k and live in a very dusty agricultural environment. Cleaning them every 10k is counter productive and again is just a failure to follow the directions provided. You shouldn't even open the air box unless you plan to service the filter. It's impossible for anyone to see with their eyes if any filter is plugged up or not. Even a clean looking filter can be plugged.

My feeling is a lot of the negative comments about K&N are from people who have never used one and are just parroting stuff they read on the internet.

jentas

The oiled air filters are not supposed to be the greatest things to run in these trucks. Something about the oil not being good for the turbo and a couple other things.

I've run them in gas trucks with no problems, just don't over do it on the oil.

I actually helped a friend last weekend with his Duramax. His truck freaked out on him and he's not too mechanically inclined. Truck threw the cel, would over accelerate before shifting, and a few other things. He thought the transmission was taking a dump. I hooked up my cheap obd scanner. One of the many codes was for the MAF sensor circuit.
I asked him if he used the stock air filter. Nope, he had a K&N. We took out the MAF sensor, blew it off, hooked it back up. Erased the codes, and surprise, the truck ran just as good as ever.

The filter had never been re-oiled, just used the way it came from the factory. He's tossing the K&N, and going back to a factory air filter.

high bid

I believe the theory is that the oil in the filter is drawn into the turbo and thus dirt/dust collects and sticks to the inside of the turbo and intake system. As we know any dirt particles inside a turbo spinning at 25k rpms is going to cause issues sooner or later. Like stated, a comparable "dry" filter is going to be the best alternative.

motochamp250

its all a farse IMO.....we have three work trucks with k&n's in them with over a million miles combined and have never had a problem......have one on the '02 as well as the '91 and on the 7.3 ferd.....ZERO problems...... i have to agree with infidel....how many people that bash K&N on here actually have one?? just my .02

John_P

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I agree with motochamp and infidel on the K&N Filters.

I have been running K&N Filters in my 1996 Dodge CTD 12 valve almost since new. I have NEVER had ANY of the problems that some people say K&N Filters cause and my truck has over 300,000 miles on it now. I have a very high dollar engine it it now with over 800 H.P. and I am still using the K&N Filter in it.

I do feel that the biggest problem with the K&N Filters is owners improperly cleaning them and then OVER-OILING them!

Just my .02 cents!

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John_P

Bluedually4x4

Actually I have ran a K&N filter in the truck along with an AEM filter and now I am running a Fleetgaurd dry filter for a BHAF. Out of the three my truck runs better with the Fleetgaurd at least according to mpg usage.

K&N is rather over priced much like Gale Banks' stuff is one of my big problems with them. Just because they are the oldest does not make them the best. Also the only way to get more air flow is 1 more surface area or 2 less restriction. Less restriction means less filtration doesn't matter who makes the filter or what kind of filter it is.

You also don't need to clean or change the filter unless the filter minder indicates you need too. That funny little thing on the air intake.

Lil Dog

The only problem I have with K&N is that it is VERY reliable on the way it is serviced to make it work properly.. And most times it gets too much oil, or not enough, dried with a hose, or not completely cleaned out before re-applying the oil over the solvent. I had a K&N on my 89 and 93 and it was fine. I just didn't like the service part of it.

The UNI in my SAII is alot easier to clean and keep serviced as I can totally pull the outer sock off and make sure its clean and dry before putting it back on. It traps all the bugs and stuff instead of getting lodged in the pleats.
IMHO of course..

motochamp250

K&n overpriced?? The cai I got from k&n was like 250... What's an afe stage 2 like 450??? Jmo

motochamp250

Not trying to start a war .. If you don't like the service of the k&n that's your opinion and by all means run whatever you want.... I'm just sayin me an plenty others run k&n with no problems and I don't know about anyone else but I'm tired of the rumors and bashing, especially by the people that don't run one .... Not saying it's the best just saying that when maintained properly it's just as good.... JMO

motochamp250

Don't mean to sound mean haha

u.s mma

There has been a k&n on my truck for about, 60,000. last night I put on my compressor upgrade and had to pull off my intake horn, and my god, it was filthy. Not blaming it all on the kn, I have been checking the intake over the last year and it is clean. I attribute to a 20yr old truck. got my oil analysis back today(first ever) and my engine is in great shape. So, who knows. I did order a custom outerwears though, peace of mind in the dust I guess. Going to keep the kn.

Gear Poet

I stopped running K&N filters when I had the same experience with three that were new-out-of-the-bag - oily dirt on the bend in the pipe before the turbo, on the turbo impellers and through the tube between the turbo and the intercooler, after a couple of hundred miles. I didn't over-oil these filters, I didn't oil them at all - they were brand new and they were letting in an unacceptable amount of dust, grit, and filter oil.

Switched to AFE PG-7's, which have a different construction and use different materials, and never had the problem again. I've seen the same problem with K&N's in a number of other trucks, diesel and gas. Good retailers like Gino's, Gold's, and others have stopped recommending or carrying them for similar reasons.

You can use oiled filters on a turbocharged diesel, if they are designed for that particular application - usually they have additional synthetic layers on the interior side of the cotton gauze layers, to retain oil and provide additional filtration. They also have a heavier wire frame on the interior filter surface for shredding control, and use a better glue where the filter material and the rubber retainers meet. K&N have none of these advantages; AFE and a few other filter brands do.

K&N's are probably fine for Vipers, Mustangs, Honda Accords, or trucks that do duty on the street or track. IMO, they're not much good for diesels or for conditions that many people drive their trucks in - occasional off-road travel, dust, gravel, mud and wet conditions, and other extremes.

But, ultimately, go with what you choose to believe, and run what you like. It's your truck.

Zeus1987

just took a peek at my turbo and it is still clean as a whistle. when i bought the K&N it was bright red which is normal for new. now it is a dark red. my grandpa who has ran them for years says it is best to let them get REAL dirty the first time before you clean it. i have had mine on for atleast 10K miles and dont plan on cleaning it until im knocking on the doorstep of 200K miles and im at 157K.