I have a 2007 Honda Accord V6 with 104,000 miles on it. Every now and then I hear a high pitched whistling/squealing noise when I start the car and when it is idling. It seems to calm down some once I have been driving for awhile. It is happening more and more frequently. Could this be a belt problem?

 

If it is a whistling noise, probably not a belt; if a squealing noise, could very well be a belt.

 

Best thing i can tell you at this point is try when its making the sound to look around under the hood and see if you can oin point about where its coming from. Ive heard small vacuum leaks make a "whistling sound" but it usually doesnt go away after a while.

 

Sounds like its time for a "Red-Neck Stethoscope" (a ~3 foot length of hose), attach one end to your ear and move the other end around until you isolate the noise.

 

Ive done that plenty of times, then theres always the long screwdriver with the handle to your ear and the other end on what ever part you think is making the strange sound.