Q&A

Sorry to hear about your past history with auto mechanics. I know I takes a certain amount of trust to have someone work on your car and if the trust is not there it make things very difficult. As for your sound, what comes to mind is an exhaust leak on your 2000 Volkswagen Jetta. This can be caused by a small hole somewhere in the exhaust system or a failed gasket. I am afraid that again you are going to have to put your trust in your local mechanic to listen to and correctly diagnose your noise.

i agree with the exhaust as the likely noise source. try to diagnose it by capping the exhaust using your hand and an old rag while running at idle (your hand may get a little warm) then listen for a noise of exhaust escaping (maybe even white tailpipe smoke since its so cold). a good exhaust system should not leak anywhere so the built up pressure should be trying to blow the rag off. as for the belt, i think they are replaced soon as part of service intervals. check your book.