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K&N Air Filters

1K views 14 replies 10 participants last post by  Lehi 
#1 ·
Has anyone had problems with dust coming thru the K&N filters?

I wish I had taken pics of mine, but I didn't think of it.

I have a drop in filter in the stock box. I cleaned the filter about a year ago I think... put maybe 2000 miles on the Jeep.

I pulled it out yesteday and the filter had a good 1/4" thick of red sand in it. From Moab, though I have no idea why there's that much in there!

Now what got me was the throttle body and intake manifold had a ton of sand stuck to the sides as well. For some reason there was an oily film, that caused sand to stick instead of all passing into the engine. The TB had a good 1/16" of sand, and the manifold had a good dusting.... I'm sure the engine injested a fair amount as well.

I had a K&N in the Dodge for a while. I went to do an oil change, so I unhooked the air tube that goes from the box to the turbo (makes it easier to reach the oil filter)... and the tube had a good amount of dust in it. Went back to a paper filter and it's been fine since.

This just happening to me? A bit of dust isn't the the end of the world, but all that sand tells me the filter wasn't working that great.

I had no problems with the K&N in the Jeep in Alaska, but it's not near as dusty.
 
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#4 ·
had something real similar happen to me with both the drop in filter and a cone filter on my old ranger. Went wheeling in a real dusty area, came back, and hada light film of dust on the inside of the intake tube. Both filters were brand new at the time and oiled correctly. Went back to the stock paper filter and haven't looked back.
 
#5 ·
I remember that article Tumbleweed mentioned. Seems that the general consenses was that it is VERY important to put a thin coating of silicon grease on the sealing surfaces to insure a good seal. I think it mentions that in the instructions. I have been running K&N for years and haven't had any problems in tow rigs, daily driver or the Dawg. We live at the end of a half mile gravel road and we get a LOT of dust going and coming.
 
#6 ·
Owyhee Rock Man said:
Actually use Silacone Dielectric grease on the seal, very easy to clean off and reapply and won't foul the sealing surface.(buy @ NAPA) Had the same thing happen to my Polaris 4 wheeler till I did that. I also use the foam pre filter in dusty conditions so I only need to clean the prefilter nightly instead of going to the trouble of cleaning the filter it self. And I have K&N or Airaid on everything I own.

Silacone Dielectric is for sealing electrical connectors from the elements, used on the end of plug wires to stop carbon tracking and spark leak @ boot to wire etc....
Yah, that's the stuff. Same stuff I use on my plugs. I also have used the foam pre-filter....Good idea. I also use the Silacone Dielectric grease to seal around the distributor cap.
 
#7 ·
I too have been using K&N for a long time(early 1990's) on my CJ-5 and added one to my Dodge Diesel after I bought it. The biggest reason I first put one in my Jeep was because I was tired of replacing the paper ones after every weekend trip into the hills. Another reason was the obvious improved filtering capibility of a properly installed oil soaked cotton filter. When I replaced the paper filter in my Dodge, I noted an increase of between 1 to 2 mpg per fill up.

So when installed correctly they filter better, improve airflow and last longer....hard to get around that.

As a side note, any test can be manipulated to show what ever out come you are looking for. Just check out some of Consumer Reports stuff. I really like the one they did on fuel effiicency estimates...did anyone think it was funny that the longer they "tested" a car stopped and idleing at a traffic light the worse the mileage was!!!???:darn:
 
#8 · (Edited)
I don't know if this is the test Tumbleweed was talking about or not, but it is a eye opener for sure. The test was done on filters for the duramax, but I would think the results would be the same on a dodge filter(or any filter for that matter). http://www.duramax-diesel.com/spicer/index.htm

A little more info. The guy that had those tests performed was contacted by K&N to visit their facility to go through some of their testing and discuss some common issues K&N filters are known for. Here is the link to the thread http://dieselplace.com/forum/showthread.php?t=66536
 
#10 ·
I've had the filter in the Jeep for about 4-5 years now, and this is the first time to get all sorts of junk past the filter. It could be that the filter wasn't sealing just right, though it was installed correctly. I should have taken some pics cause you guys would have been :shocked:


On the Dodge, it came with the K&N. The first oil change I did, I saw a bit of dusting in the air tube. I cleaned the filter, oiled it and next oil change was the same. I wasn't going to risk a $6000 engine to a filter than kept on passing dust.
I put a Napa Gold paper filter and I have not seen any dust in the tube, that filter has been in place for over 15000 miles.
 
#11 ·
Interesting test. looks like they put alot of time into it.

Question: Why the 350 CFM limit??? Doesn't that seem low considering we are talking about turbo fed large displacement Diesel engines??

Notice on the "Accumulative Dirt test" that the filters weren't compared..the test was comparing the individual filter against itself. What was the freeflow vs restricted flow for the individual filters?? What was the "plugged" readings for each filter?? How do they compare to eachother?/

Like I said eariler, you can create a test to verify any point you want.

Personally I will stick with my K&N's.
 
#12 ·
I think it all comes down to maintenance.....

like said before 350cfm is a low amount of air to pass through a filter. And K&N suggest using a pre-charger if you live in a dusty area.



Just because they have a million mile warranty, doesnt mean you drive it for that long before servicing it:rotfl:

I end up cleaning the filter on the buggy after each comp due to all of the dust, but the tow rig gets it at each oil change.
 
#13 ·
How do you put the pantyhose things on the drop in filter?
 
#14 ·
I ran K&N filters for years and have hated everyone. I didn't notice a performance gain, but the constant cleaning and oiling sucks. Plus, I always had dirt inside the throttle body even after trying several different air cleaner housings and ducting. Still never improved. Finally chucked in the trash along with all the K&N oils and cleaners and have never looked back.



 
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