Hi all,

Experiencing a light, rapid ticking sound coming from the right front passenger footwell. It pops up whenever I'm doing 75+ mph (more frequent the faster I go, independent of throttle position), and also when accelerating from a stop (varies with engine speed, but in this case it disappears when I lift the throttle). Putting the gearshift in neutral will sometimes make the ticking go away, and sometimes it won't.

FWIW, We had a rebuilt transmission put in the car earlier this year, and the noise has slowly developed since then. I can't figure out if this is an engine thing or a transmission thing, and figured I'd just throw it out and see if anyone had any idea where to start looking.

thanks,
anthony

Or an exhaust leak?

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Benzmac:
Donnie Drummonds
300E
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM
OWNER OF MB AUTOWERKS .COM

Something similar happenned to me, when a non-MB mechanic put the hanger (coming out of the rear of the transmission) for the exhaust pipes UPSIDE DOWN! It was hitting the bottom of the passenger side on bumps, acceleration, etc.
You never know!

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J.H.
'86 300E

Thanks, it was this sort of "but have you checked.." reply that I was looking for.

anthony

Hmm, I wonder if the engine is torqueing over due to a motor mount that has gone soft. Maybe...sounds like a load related noise from something going tick in the night..

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Jeff Lawrence
1989 300e
2000 Dodge Grand Caravan SE

Actually, that might be the case too. The motor mounts are about 50k miles and a few years old, so they might be due for replacement pretty soon. I've been digging through the cd looking for the entry on motor mounts (anyone know of the number offhand? ) I also gave my exhaust system a visual inspection - there are a couple places near the exhaust manifold where clearance is tight and there might be some contact, but I tugged the parts around a bit and didn't feel any movement. I didn't see any parts damage, will have to try sealing off the tailpipe tomorrow.

Upon further investigation, I've discovered that there are multiple things making noise with my car. There's a rustling noise that varies directly with engine speed, and I think this might be traceable to the exhaust system. There's also another ticking sound that occurs when the engine is under light load - it disappears with acceleration and when I completely lift off the throttle. I haven't decided if this is the same beast that pops up on the highway. And all of the sounds seem to be coming from the front passenger footwell.

The mystery deepens...

thanks,
anthony

p.s. As a sidenote, it's amazing how quiet these cars are with the radio and hvac off. I think below 40 mph, the fan blower is louder than the wind, road, and engine noise combined..

Nevermind on those motor mount pages, found 'em.

anthony