Whistling noise on start-up

When I start my truck (cold start), there's a strange whistling noise coming from somewhere in the engine for about 20-30 seconds. I cant describe it much more in detail than that. I've started the truck numerous times with the hood opened up, but I cant place where the sound is coming from. Any ideas?

 

This winter mine has been whistling too when it's really cold out, 20 and below. It goes away after it is warmed up. I wouldn't worry about it.

 

sounds like your whistling fluid is low. Need to go to the dealer and buy a jug.

 

And try not to eat too many crackers before starting .

 

Maybe someone snuck in and installed a turbo while you weren't looking...

 

might be building up vacuumb?


or maybe youre secretly running it off hydrogen

 

mine does the same its somethin to do with thst smog thang that sucks air its in front of your airfilter housing and it looks like a snorkle or something thats all i no

 

I have this whistling sound too but I'm in Southern California, where cold is not really an issue.

Is there someone with serious answer?