sounds like supercharger under hood first min of driving

[ccanuk]

Hi there

I've been hearing a strange noise for a while, and figured I should find out what it is.

When I first start driving while the engine is still cold, I get a sound from under the hood that sounds like I've got a supercharger under there, like the winding up sound they make...

is this normal? is it the IAT?

it goes away after a minute and doesn't come back till the next time I start it.

any ideas?


thanks

 

[Mbrooks420]

Could possibly be the IAC. Does it go away when you give it gas?

 

[ccanuk]

no, thats why it sounds a lot like a supercharger, the frequency of the whining increases proportionally to the throttle, but it goes away after driving for a minute once I've gotten up to driving speed

 

[Brock94]

Could this be the radiator fan-- the clutch on the fan is always fully engaged when you first start and after a minute or so, it shuts off.

 

[1995_Ford_XLT]

I had a similar problem--only did it when cold shortly after startup. I tried several times to track it down but never could--that is, until the serpentine belt tensioner let go, making a very loud bang and falling out of the bottom of my engine compartment in pieces. Replaced the tensioner, and the problem hasn't returned.

Have you recently replaced the serpentine belt? Has the tensioner ever been replaced? No guarantees, but this could be the problem.

Good luck!

 

[performancenut]

I had a vehicle that ended up with a warped header and had a high pitched whistle also which would resolve by the time it reached operating temperature (the metal would expand when getting hotter and essentially seal the leak until the next time of a cold start).

 

[bill.moulton]

Sounds like the fan clutch.

My 91 had the same noise for a while. Sounded like a Cesna taking off.
I replaced the fan clutch and it is fine now.
Easy job to do if you get the wrench set (about $20.00 @ Pep Boys) that is
made to remove the fan from the clutch.