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K & N Air Filters

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Posted 08 April 2014 - 02:01 AM

Hey, I've seen some topics that talk about these K & N oiled reusable air filters not being approved by a lot of OEM engine manufacturers, especially in the diesel forums. The claim is that these filters let in more dirt with the improved air flow. I am under the impression they are blowing this way out of proportion severely and here's why: 

I have a gas burning light truck that has had a K & N in it since before I owned it. Now it has almost 200,000 miles on the engine and it doesn't even burn oil! That's a lot of miles for a gas engine! I've overhauled lots of engines in my days and have never seen any engine last anywhere near this long that has been getting much of any amount of dirt in it! On top of that, I don't even clean or "regenerate" this filter near as much as it is recommended.


I think K & N has been getting a major bummed rap here.


I know that getting the sulfur out of the fuel has had a major impact on engine life, but dirt is dirt and no engine will last long if dirt is getting in.


I also use full synthetic oil, but that won't save you either if dirt is getting in.


I need to make a post on synthetic oil, I'm a firm believer in it and with good reason. My late father was a chemical engineer that designed many refineries and chem. plants. Hydrocarbon science has progressed considerably in the last 40 years.


Speaking of that, where did that 26 cents a gallon gas go! When I was in high school, I could fill up for less than $5. Now days that will just buy a gallon.

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#2 kaypsmith


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Posted 08 April 2014 - 08:12 AM

AMEN Bro., clean air and slick oil is the key to engine life!!!!

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#3 HenryPatterson


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Posted 08 April 2014 - 08:32 AM

I agree with you...I've got a 90 ford p/u with a diesel in it...bought it new.  Never had any thing but K&N filter in her and she now has over 500,000 miles on her,and still going strong.. My new Monaco has one in it also!!  K&N has been in business a long time and wouldn't be if they weren't doing it right..

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#4 wolfe10


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Posted 08 April 2014 - 08:44 AM

OK, just an observation:


Both Caterpillar and Cummins recommend AGAINST any of the oiled filters.  Yes, they let in more air, but also more dirt. 


And, certainly in Caterpillar's case, they have no "skin in the game"-- they do not sell air filters for any of our applications.


BTW, what are your air filter minder readings that are leading you toward other filter choices?


I do agree that restriction in the intake system of a diesel should be addressed, but that is what the air filter minder does-- alerts you to a problem.

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#5 DickandLois


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Posted 08 April 2014 - 09:54 AM

Reading posts regarding air Filters is always interesting.

I have used both oil and dry filters. The one item that gets over looked and misunderstood IMHO is how much oil one uses after cleaning K & N filters when recharging them.


Many think more oil is better. With the advent of the Mass Air Flow Sensor, oil on the sensor can mess up the readings sent to the ECM. Along with the readings of the O-2 sensor(s) to control combustion.


Engines are really big air pumps with a 13.7 to 1 ratio of fuel to air. With the advent of the ECM that number is being constantly tweaked, along with the Ethanol content sensor in the flex fuel engines.


With the drive to get more HP from smaller engines Turbos are common, more air equals more particulates and they blast away turbo blade material that adds even more abrasive material going through the engines.


 Diesel engines live by the same rules.

There are always trade offs.


I remember when the Farm equipment used oil bathed filters and needed to be cleaned frequently, The dry filters of the day did not last long in the dust and organic matter flying around and engines just looked at some extra hydrocarbon as no real big deal..



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Posted 11 April 2014 - 10:21 PM

If you want facts . This is a link to a filter test. You might want to read it if you are using a K&N filter. This is the only test that I have seen that used lab test equipment to do a test that is repeatable and to a given standard ISO 5011 test standard was used.


I think its interesting that K&N will not release their test data. When you look at their web site they brag about how much more air their filters flow but you can't get them to release test on dirt passed. I have used K&N filters on my old truck but no more.



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Posted 12 April 2014 - 06:55 PM

When Cummins says don't use something...I don't use it.

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#8 Planocat


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Posted 13 April 2014 - 09:34 AM

IMHO, and I have used K&N filters in the past, it's snake oil. Can't see using anything the engine manufacturers advise against using. Maybe great in racing engines that are frequently rebuilt, but I don't believe they should be used in engines where longevity is a major concern. Again, to each his own. Give me OEM or Wix and I'll forgo the performance increase....if there is one.
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