IAC or TB? Howling from under hood
 

Hey all. My folks have a 95' Explorer I believe its the 4.0 motor. The engine is making a howling noise and I have traced it back to the Throttle Body area. Would the IAC make this noise? I have been searching this site and the net and the only thing I found that was closely related was a post on the IAC and the possibility of it making this noise.

The noise is really loud and constant, it sounds like a kid blowing air through a pop bottle WOOOOOOOOOOOOOOOOOOOOOOOOOO. Any ideas on how to check before I start replacing? Any help would be greatly appreciated.

Clean your AIC that should fix the problem, Common

Yep, there are lots of threads on this site for cleaning the IAC.

IAC fixed it on my '99
 

I had the same thing on my 99 explorer and I replaced the IAC for $60, top of the engine, two screws, easiest repair you will ever make. An easy test - if there is a black cylinder shapped hard cap sticking out the side, pull it off while running and see if the noise goes away.

When I replaced mine, the original had no rubber gasket and the replacement came with one. The loose metal on metal fit of IAC attachement might have been the cause of the whine.

My 1999 4.0 OHV Explorer was "moaning" and I replaced the IAC to fix it. When it started again, I replaced the thin gasket between the IAC and throttle body with a thicker hand cut gasket and the problem went away. I think the thin IAC gasket acts as a reed and causes the moan since the hole in the gasket is smaller than the air passage.<!--IBF.ATTACHMENT_178600--><!-- THE POST -->

I have this same problem - but it is coming from the Aircleaner box - I did remove the IAC and cleaned it, and then reattached it - it didn't make the sound before, but it really really done now! it's really loud!! is that the IAC not seating correctly on the side of the TB? and the air that is getting past is causing the vibration?

I should have just left it alone - but I was just trying to do some PM - since I had the can of TB cleaner handy... man the plate looks so clean now - was black around the edges there - brown coffee pouring out of the end of the TB -

should I just go get a gasket, and make my own? cork? or what? There was no gasket there at all when I pulled it - it is the original unit.

Thanks

UPDATE:

I tried the "remove the black cap" trick, and it WORKED! do you really need that black cap on there anyways? air is just coming out - I guess it's to keep stuff from entering inside there -

if I could come up with something to use for that, instead of the black cap, the noise is gone!

why is it doing this anyways? ill fitting mounting? should I just get a gasket?!

Thanks to all

My IAC had a thin paper/fiber gasket. I cut a new one out of some 0.030 or 0.040 thick fiber gasket sheet material. If your IAC didn't have a gasket, it doesn't sound like this will make a difference.

Hi,

That is interesting - I'll try that - even though it is mounted to plastic TB - they are plastic, not metal on the 96's and up - at least the 4.0's are - as I said, it totally goes away if I just pull the cap.

But, it's maybe like you said - because maybe when the air is restricted, it moves through the small space between the TB and the unit itself on the mount -

so, I guess I do need that cap on there?