K&N question

[Ethan0524]

Any ideas?

I have a K&N full cold air intake on my 2007 4.7, and for some reason on startup it hisses extremely loud, I mean ear splittingly loud. Even when the hood is shut, if I'm standing in front of the truck I have to YELL at the person next to me to be able to hear over it...I sort of believe that this is not proper operation of an intake? Also, to emphasize, it really only does this on startup. I understand that an air intake will hiss as it sucks the air in, but not like a freaking jet engine. I've never heard an air intake make this kind of sound on any vehicle. I've checked for vacuum leaks, I've checked and cleaned the IAC and TPS, I've checked all the connections and everything is tight. This didn't happen with my last RAM or any other vehicle I have ever seen with an air intake of any make so I'm wondering if I just got a bad intake? I've removed it and reinstalled it twice with no change in the ear splitting hiss. Also, I have been doing a hell of a lot of searching and can find nothing quite similar to my situation anywhere. Any body have any ideas? Any and all help is appreciated!

 

[Harley Harrold]

Check around the throttle body for an air leak also check where breather hose and air intake temp. sensor is mounted for air leaks.

 

[Ethan0524]

I've checked all the connections, everything is tight. No air going in where its not supposed to be, at least not that I can find. I'll keep checking though, its getting really frustrating. Thanks for the reply!

 

[CorDog009]

The only time I've heard a noise similar was when an AIR injection pump would come on to help pre-heat the cats, but these trucks don't have those...hmm.

 

[Ethan0524]

I'll probably just end up saving for another one of a different make, not sure if it is the intake or if its my truck. What are some other good intake brands that you guys use?

 

[DDean]

I have one on my 4.7 as well. Its kinda loud at startup then goes away. Only thing annoying about mine is i have this whistling sound from time to time that has kinda gotten on my nerves a little bit but i try to ignore it

 

[Casper]

Do a chalk test on the seal to your hood. A small gap may be causing your hiss/whistle.

Then check the area the K&N draws from in the fender--there may be an obstruction causing it to suck air past the hood seal.

 

[DDean]

Cant say thay i know what a chalk test is

 

[Casper]

Are you ready for this?
Step 1 put colored chalk dust on the upper edge of your K&N box.
Step two close hood.
Step three, open the hood.
Step four examine the chalk transfer to the underside of your hood. If not a perfect match of the chalked surface below, you've found your whistling gap.

 

[Ethan0524]

Are you ready for this?
Step 1 put colored chalk dust on the upper edge of your K&N box.
Step two close hood.
Step three, open the hood.
Step four examine the chalk transfer to the underside of your hood. If not a perfect match of the chalked surface below, you've found your whistling gap.

Well, I'll try this out, thanks for the reply!