name that noise...

[EliteConcept]

whasss up everyone

97 expo with just under 70k on it...
ok so heres the situation, this has been happening for a while now...when my truck is running i get, i guess its decribed as a whril, it really sounds like its coming from the belt, or more specific the ac compressor pulley...when i shut the truck off the whril doens't stop right away it sort of tapers off you can hear it slow down and come to a stop about 3-5 seconds after engine has been shut off..

the belt doesn't exzibit any signs of wear.
doesn't cause driviablitiy problems...just hate the sound of it

if i had to guess i'd its something to do with the belt...
i'll see if i can't get a sound file of it for you guys...i hate this noise.

any help appreciated.
ryan

 

[dreamr]

Hmm I am subscribing o the thread because I have had my truck in twice for the same situation, I have replaced the serp belt, fan clutch, and serp belt tensioner.

 

[IAmTodd]

Just tell people its your supercharger!!! Could it be your fan coming to a stop?

 

[EliteConcept]

could be..BUT it doesn't really sound like a noise the fan would make.....its more of a whril sound you could make with your mouth..grrrr hard to decribe...

 

[Cali' Explorer]

Ok, I've had similar sounds. Based on what you're telling me its hard to say exactly which of these it is, but these are my suggestions.

1.) Main Idler Pulley (the one on top in between your Power Steering and Alternator). I had a similar noise for a while that soon became more of a squeak, ended up being the bearing in the pulley dried up.

2.) The belt tensioner pulley. The springs have a tendency to lose tension and the bearing's go dry.

3.) The A/C pump making happy little noises.

4.) The IAC making its nice little howl sound.

The fact that you say it lasts a few seconds after you shut off the engine lease me to believe that it is something not directly connected to the engine though.

The way to test 1 through 3 would be to disconnect the belt altogether and start the car with no belt, listen for the noise (drive it around the block if need be, but be careful, no power steering). If the sound is gone, the next step is to check the pulleys. If its them, you'll feel it when you spin it. Third, there's a wire that attaches to the A/C Pump that if you disconnect it will eliminate the electromagnetic clutch on the pump. If you have this disconnected and its still making the noice, its one of the pulleys.

For 4, there's numerous documents on how to check/clean the IAC on any engine, just use the search.

These are my suggestions anyways.

 

[EliteConcept]

very intresting...well i can elimiate one of them right away i cleaned my IAC just a few months back.. the rest though i may have to try

 

[drummergirl]

Check out the video in this thread. Is this the noise?

http://www.explorerforum.com/forums/showthread.php?threadid=85293&highlight=iac

 

[mhn3773]

i dont understand something..u say when u shut the engine off it continues for a few secconds..is the belt still spinning on the engine? or has that come to a full stop and the noise is still there?