If the wheel bearing becomes loud doing acceleration, does it need to be repaced

I'm not sure how oil gets to the wheel bearing, unless you have a massive oil leak covering the entire front of the car. Sounds more like normal wear on the wheel bearing. Welcome to the world of used, past luxury cars.

I can't provide a direct answer, but I can give you the benefit of my own experience. I have a 2006 A6 Quattro 3.2. At roughly 90K miles, the clamp on the front right outside drive shaft boot just disappeared, slinging grease over all related parts. The CV joint was toast, but so was the wheel bearing. If the noise you are hearing becomes louder when the bearing is loaded (when you are entering a turn on which the bearing in question is on the outside, weight bearing side), then the bearing is toast, and it needs to be replaced. Oil in the wheel bearing could dissolve the grease in the wheel bearing. I just replaced both half-shafts and both wheel bearings in the front of my car. It feels like new. P.S: If you're going to replace the half-shafts, talk to Marty at Raxles in Gainesville, Florida. The guy knows high-performance half-shafts as well as anyone, and it is REALLY easy to do business with him. No, i don't have a dog in that hunt.