Also check the tensioner pulley. If you can, spray it while the car is running and its chirping and see if it goes away. My 95 Bonneville does this and it's the pulley. Dobbs thought it was the belt as well even after I told them it was the pulley ( I know because I hit it w/ spray lithium grease and it stopped for a bit) and they replaced the belt. Guess what, about 1 week later the noise came back.