I recently had the Power steering pump replaced by my MB dealer. I had orinally brought the car in because of a leak, and had the assumption that it was the clamp. They told me the entire pump needed to be replaced. 3 Months later i notice a whining sound on a cold day. After searching here i find out that the sound may be caused by low PS fluid levels. I go home add MB PS fluid, took about 20ml to fill. An low an behold problem corrected. Should i take this back to the dealer or what?