Ali and Bmerc, the noise looks like coming from the front of the engine near the radiator from the outside listening. The serp belt looks like it has the worn look with very small cracks in the ribs noted, but doesn't look new at all like the one in my 1984 C180 which was replaced 2003. Is it necessary to change both parts, tensioner and belt at the same time? Shouldn't the tensioner also make the same noise at idle in N? Why is it quiet at N and makes noises when in gear? Bmerc, the 1997 model I have has the 5 speed auto and the 1994 version I have has the 4 speed auto. Thanks buddies.