Hi guys can everyone please give me some ideas on what your early 80's volvo's sound like motor wise? Mine developed this new sound it seems to be coming from the front of the camshaft I recently changed the timing belt and tensioner, it sounds like "purring" and its a new sound. I hope it is just the sound of the new tensioner but with my luck I doubt it, like i said if I put my ear to the timing belt cover (minding the fan of course) on top of the cam I can hear it really well. Now I am a bit anal about sounds and the car doesn't seem to be having trouble but I can't ignore a new odd sound. It also seems to go away when I rev the car up but when it gets back to idle I can hear it again, it may be an exaust leak but again I doubt it. Any help you guys can give me would be great.

The car is an 82 245 GL NT.