Only at idle and not all the time my 1999 XLT 4.6L sounds like it has a moose whining under the hood. If I put it in neutral that is enough of a RPM increase 'usually' to stop it, sometimes I have to hold the gas a bit because it's really loud and embarrasing really. Any idea's guys??

 

Well i've never heard a moose cry but i'll give this my best shot. First i would check the belt, make sure it's in good shape and not glazed. Second would be too look around under the hood with the truck running and see where the noise is. It could be the bearings in the a/c compressor, alternator, power steering pump, etc.

-Jon

 

It is the K&N FIPK. My AIRRAID did the same thing (as did most others on this board). All I had to do was call them, and they offered a solution. Maybe K&N has one for you.

 

Thanks I'll call K&N.

 

Ford4ever

I'm with you on this one, I think it's the serpentine belt or the bearings. However, it is also possible that his alternator is shot. One way to check is to take a long tube of metal or something (I don't think a clothes hangar will work) and touch the alternator with the engine on. Be CAREFUL around the belts and the fan. Put the tube near your ear. Move it around and touch different things and you'll notice the sounds should change. Where it is the loudest, well, that could be what's shot. Dunno if it works or not, I use a stethescope to locate sounds, but give it a try.

 

defacto,

We always used to use a long screwdriver to acheive the same, amazing how the sound would travel up to the handle......

 

mine does it too,k&n doesn't have a fix for it.i put new rubber 5/8'' heater hose in place of the stock vaccum lines for the crankcase vent and the idle control valve and slipped the stock airbox with the end cut off over the k&n and it made it stop hissing,but then the moaning started.you could put a restrictor on it,i squeased the icv line and it stopped.

 

Might want to check the the fan clutch. I had my fan/clutch replaced after I only had 1000 miles on it because it made a funny screaming sound, but only when idling. The second you increased the rpm the noise went away.

I have the K&N FIPK and do not have the problem however I do have a faint whistling noice when the weather is cold and I'm off the gas decelerating. The noise is louder the faster I'm going. This is normal according to K&N since the FIPK does not dampen intake noise as much as the stock filter setup.

 

Yep, sounds like the Airaid idle whistle.

CHeck the idle control (I think) hose. While it's idling/whistling, pinch the hose and see if that changes or stops it.

Airaid sent me a whole new tube to test for them. Just after reporting success to them, they came up with a less expensive alternative. A reducer for that hose fitting.

If your K&N has the same issue, try finding a way to reduce the ID of that hose fitting without somehting loose that could get sucked up of course!