About 3 or 4 years ago I had noise coming from my power steering pump, I have the 2.2l. It was leaking slightly so I got some lucas oil power steering stop leak and haven't had a problem since then.
http://www.lucasoil.com/products/dis...tid=9&loc=show I've always been skeptical of stop leak products but it really worked. And it made the pump quiet. I sucked out all the fluid I could from the power steering reservoir with a pneumatic brake bleeder and poured that stuff in.