2.0TS:vibrating sound b/w 2000 and 3000 rpm
Hi, my 156 2.0 TS'99 exhibits the following symptoms:
- vibrating sound with a tremolo effect (variation in amplitude) between 2000 and 3000 RPM when cruising and coasting/slowing down. Not noticeable when accelerating. Looks like the source of it is the engine or the front part of the exhaust.
- slight vibration when pulling away - heard, not felt; the source seem to be in the engine area. The clutch action is smooth.
- engine mounts - the bottom ones seem OK, but I could not see the rubber without dismantling them; I was able to move the top of the engine by about 1 mm with significant effort, so the top one also seems OK.
- exhaust - the bracket in front of the engine is OK, the bottom one just before the flex pipe is OK, but the rubbery part has partly melted away. Should there be solid/permanent rubber bushing action there?
- belts, pulleys, water pump - changed 1 month ago. What would the symptoms of badly fitted balancer belt be?
- exhaust manifold shield - checked, seems tight
- heat shileds above the exhaust pipe/catalyst/silencer - checked, seem tight
Has anyone experienced these symptoms and resolved the issue before?