My audi a4 quattro 02 3.0 is making this knocking sound. We just had the water pump replaced along with the timing belt. We got it back and its not over heating anymore but when you start it, it idles between 1000 and 1200 rpms a bit high. Along with that there is a knocking noise that has just now started getting worse. Im about to go get the codes ran but was hoping that maybe someone would be able to help identify the problem and have hopefully give a solution that is cost effective.

 

If you just got it back after the water pump was done, that's some major work on the 3litre, you should be going back to the repairer.