Whistle on cold start

[Hubba730]

Hey guys. I have 03 4.7l and get a whistle sound from engine bay on cold start. Goes up and down in intensity with rpms. Goes away when warm. It's not power steering. Any ideas?

 

[Minn3sota]

I have an 04 4.7L and I hear the same thing on very cold days. I've often wondered about it too. I can't be absolutely confident, but I swear the noise emanates from interior vents.

 

[bopp95]

I have a 08 4.7 and hear the same noise. Mine will go away after a few minutes of warming up though. Not sure what is was but only noticed the noise this winter, not in the summer.

 

[black4vcobra]

I have an 04 4.7L and I hear the same thing on very cold days. I've often wondered about it too. I can't be absolutely confident, but I swear the noise emanates from interior vents.

Same thing on my 06 V8 when the temps are down in the single digits. I've thought it came from the blower motor too, I will try to remember to turn off the fan next time I start the vehicle on a real cold day.