Whining noise

I have a 2001 four door tacoma prerunner, 3.4 V6 with 103,000 miles. I've notice a whining noise coming from the front like in the engine compartment. But the sound does not change with speed and does not occur all the time. It sounds like as if something were letting off air pressure like an air valve? Anyone have this similar issue before or might know what it could be?

 

According to the aamco commercial where people make funny noises to explain their car issues, I'd say cracked radiator? Going by the sound of the guy letting air out of a ballon slowly haha.

Sorry I couldn't be more help. That commercial was the first thing that popped into my head.

 

Ha ha, funny.

I've read a few different thing it might could be.
Wheel bearings or the Alternator?

I won't really have time to look at it more until
Monday or Tuesday when I'm off work.