K&N Filter Whistle??

[gijoecam]

Ran a search, but I don't remember anyone ever mentioning this either, so here goes....

98 Ex XLT 4.0 SOHC Bone stock except for the K&N I dropped in the other day... Since I installed it, I have a very high-pitch whistle that varies with engine RPM. Above 3000 I can't hear it, but It could very well be drowned out with road/engine noise. Wheel speed makes no difference... like I said, it varies strictly with engine RPMs. I dropped the old Fram filter in and the noise went away, so I am sure it can be attributed to the K&N. I also did install the rubber gasket around the under-side of the top half of the filter box, so I'm pretty sure I'm getting a good seal.

So, the question is, has anyone else experienced this? Did I get a bum filter somehow? At first I thought it sounded cool; almost like I had a blower on the engine, but now it just grates on my brain like a block of cheddar on a cheese grater!! After a rough day at work it's almost unbearable with the windows down! I don;t think I can return it because I already applied the gasket... suggestions?

Thanks, gang!

-Joe

 

[Black Magic]

Yes, mostly all the Open air filters have a whistle. That is a common complaint.

 

[ton_e_montana]

hook up a chip and exhaust and you'll forget all about that whistle

 

[tturse]

That seems to be normal for the K&N filters- I was told it is caused by all the xtra air being forced through the filter/intake- I just cleaned the one in my Audi 80Q and the noise is back- it seems to go away after a few months- I guess when the filter begins to clog. I definatel notice a bit of xtra pcik-up in the Audi so I live with the noise.

Thomas
Denver, CO
97 XLT SOHC

 

[Alec]

Try drilling some holes in your airbox so the filter can get some more air. It may be that it can't get the air it "needs" through the restrictive stock route.

 

[gijoecam]

At higher rpms, I could understand having a bit of a whistle, but it would be drowned out by the rest of the engine noise. I spent some time on with K&N Tech support, and the guy said, "I'm not an engineer, but it's probably because the K&N filter is moving more air than a stock paper filter." I tried to explain to him that I am an engineer, and that at a 600 rpm idle, the engine is moving a fixed volume of air, whether it's pulling through a K&N, paper filter, or no filter at all. The variable is the filter and the filter alone. All the hoses and fittings are tight, and simply dropping the old Fram back in eliminates it (I have run Fram, Motorcraft, and Purolator filters with no problems in this application before the K&N).

He basically left me with two choices: 1) Return the filter to the store. or 2) They will send me one and I can send the whistler back. Not sure which I'm going to do yet, but I doubt the store I got it from will take it back, because I already installed the gasket, so I may do both... let them send me a new one, send them back the old one, and return the new one to the store.

Drivin' me crazy here....

-Joe