Are you sure the P/S is the source of the noise???The pulley on the A/C compressor may be the problem. When they fail, the sound is very similar to a P/S type noise. The way we diagnose this at the dealership is to install Poly V-Belt #011-997-96-92, or it's equivalent. This belt is shorter than the original, and can be installed in such a way as to eliminate the A/C compressor from the loop. If the noise goes away, the A/C pulley is the problem.