Yesterday they were installed by a performance shop and they didn't make a noise. today while going to a restraunt they starting making whistling noises. whats does that mean? Is it reasons for concern? Please answer someone . Nobody from 2005-2006 Mustang section will answer.

 

it may not be all the pulleys making a noise, maybe your idler pulley is going out also check your belt tension or belt wear because often squeaking noises can come from your belt

 

i would check the belt

maybe take it back to where it was installed

 

Today I had some people at work look at it and everything appeared o.k. One said the it could be the idle pully going out the other said its a new rotation for the belt. The shop said its common when switching pullys. Monday I'm going to have them look at it.

 

Umm, Throw a new belt on it and I bet it goes away.

 

What kind of belt are you running?

After I went with a UD WP pulley I used a Goodyear Gatorback and that SOB whined/whistled like a supercharger after being on the car for a couple days.