hey, im new here and i have a couple questions to anyone that can help me. Lately my 98 ML320 is making a ticking noise around my timing belt when i am at IDLE. I am also noticing that my IDLE is a little low, maybe around 600 RPM's, give or take. But the ticking noise goes away while im actually driving. But once i stop, it goes on again. People have been telling me it might be my timing belt and i might need to change my tensioner, belt, and water pump. Might the problem be anything else?