k&n air filter bad?

[ataboc]

I have a 1999 F350 PSD and I put a K&N air filter in the stock air box. I had a mechanic tell me that he had read recently that the oil from the filter would cause problems in the engine. He wasn't specific and I didn't get a chance to have him elaborate. Has anyone heard of this? I was planning on eventually going to a cold air induction system, probably K&N but now I'm causious. Any thoughts would be greatly appreciated.

[chuckster57]

You have entered the land of the GREAT FILTER DEBATE. You can search the forums for air filter recommendations and read til your eyes pop out of your head. Some claim that it doesn't filter enough and you "dust" your turbo and engine, others have claims of thousand of miles with NO issues. IIRC the main issue with the filter oil is it causing the MAF sensor to fail.. I have an IDI so I don't have that problem. get ready for a barrage of replies from both sides

[ataboc]

LOL. Thanks Chuckster. I'm waiting with baited breath.

[SmokeyWren]

There are two things wrong with a K&N air filter in a stock air box.

1. The stock air box is a lousy design, and tends to leak unfiltered air past the filter. That can be disastrous.

2. Too many people don't know how to maintain a K&N filter, so they screw it up.

There is nothing wrong with a K&N air filter, provided you are certain it fits perfectly in your air box so no unfiltered air can get by it, and provided you know how to clean and re-oil it using nothing but the right kind of oil.

I had one for about a year. I threw it away and replaced it with a much better intake system.

K&N now makes the big conical fuel injection performance kit (FIPK) intake system that replaces the lousy Ford air box. That's a good aftermarket air intake system, but again, provided you know how to maintain a K&N filter.

Much better is to install the new Ford Severe Duty Air Induction system (AIS). The only maintenance is to replace the filter every coupla years. About $200 steet price, and there is no better intake on the market for producing up to about 400 ponies from your engine.

[escs36]

i originally put a drop in kn filter back in 2002. when i went to service it, it was destroyed. it appeared that the engine tried to suck the filter in. the ends had collapsed and the engine was eating unfiltered air. i then replaced the stock box with the kn conical deal. it has lasted since 2002. i still believe that the other companies are the way to go. i just did not know of those companies back then.

[JerryKing]

For what its worth, I installed a K&N FIPK system on my truck, and then I read bad things about K&N filters on this site and, in particular, that they have small holes in them that let too much dust through, and that Airaid filters are better. So, I bought an Airaid conical filter that is the same size as the K&N. When I shined a flashlight through them, I could see tiny points of light coming through the K&N filter, but not the Airaid filter, so I installed the Airaid filter. Does the Airaid filter really do a better job of filtering dust than the K&N? I have no idea. All I can say is that I've had the K&N/Airaid filter system on my truck for a long time and it has worked well.

[1st Synthetics]

From tests that I have seen in print the K&N is the worst at filtering. Any filter that you have to oil to fill holes in my opinion is a bad thing especially on a Diesel. I used to use K&N filters on everything I owned years ago, not now.

[Bwlnt]

I put a square K&N filter in my trucks stock air box and have hated K&N ever since. Fortunately I read some posts shortly after the install about how bad K&N square filters are and checked my intake and did find light dusting between the filter and turbo. This was after 10,000mi. in non dusty eastern U.S. conditions. My turbo fins are still sharp so I don't think I hurt things too bad but still. On this principal I will never buy K&N products! They strike me now as cheap toys that can really mess up a fine work engine.

[jroller]

All the above threads seem to have a pattern. None of them have lost an engine do to a filter and I doubt KNN could ever stay in buisness if they constantly had to replace people engine and turbos in court.
If your worried about "dusting" your turbo then ad the filter cover they sell.
Just to clarifey I have had no less than five 300hp plus turbo cars, +1 diesel truck (with 177k with a KNN FIPK). For work I routinely drive the truck from San Diego to Yuma AZ, going from sea level to 5,000 ft 15% grades. The ambient temp by the time Im up that high is usually 95-115 degrees in some of the dustiest, sandiest conditions. Never an issue with my stock turbo, no pitting of my impeller blades.
I must admit that I was concerned because I drove so many miles before finding on these forums what a poor reputation KNN has in the diesel community. Through my own expierence I was able to logically conclude that, in my case, it had worked just fine. I realized KNN is a huge target and sells more aftermarket performance filters than all other reusable filters combined.
As far as oil getting into the engine its a focking diesle truck AKA OIL BURNER! People run these on used transmission fluid and french fry grease.

Lastly, make your own desicion, experiment yourself and formulate your own opinion.

[fire370]

I honestly don't believe a "wet" filter belongs on any diesel engine, whether they are maintained correctly or not.

[amthatiam]

I bought my truck with 39,000 miles on it, previous owner had a K&N in it, when I installed a bunch of mods and had the turbo out I was amazed at the damage to my impeller wheel in the turbo, blade edges rounded and badly dinged, installed WW and ford AIS and 100,000 miles later my impeller blades are as sharp as they were new and my intake system is amazingly clean, just the light coating of oil from the CCV. I will never use a K&N again. The only problem the oil on the filter can cause is MAF failure.
Dan

[coplin]

I see two sponsor ads for K&N beside and below this thread!!! bwahhhh!!

Keep it clean and don't OVER oil it. Make sure it seals tight no air leaks. I believe any issues encountered is from not maintaining the filter properly.

I'm agree with the guy above, it's made out like K&N has a secret mission to purposely destroy thousands of diesel engines. After so many years at it, why would they want to sink their company? Maybe it's bash the other guy so we can sell our new product syndrome I dunno..........

[chakaman123]

i have a knn on my 01 just to be sure it seals i put a thin coating of rtv on the filter and sprayed cooking oil on the top box to keep the rtv from stiking to it iv put 10,000 mile on it and still filters good

[Sleeperstroke]

K&Ns are not for diesels. There are many waayy better choices. Yall using them with "No problems"..... Good luck with that..

[Cowcop]

I have 10 years with K&N FIPK on this truck and go back another dozen or so years with other vehicles both diesel and gas. Guess what? NO PROBLEMOS! This is backed by excellant Oil Analysis results!
As said, K&N is not being sued for damages, they sell thousands upon thousands of filters for our style of vehicle and IF maintained properly, caused NO ISSUES!!
We all have opinions, some are even based on personal experience, but read all the threads carefully and you will warm up to something that is great for your purposes!

Best of luck and NEVER start a K&N thread again!