Hi,
My 1986 245 (4-speed manual with electrical overdrive) has started to make an odd noise when I start from a stop. It's a sort of metalic resonant sound, almost as if one were dragging a metal shovel across pavement. The sound only occurs when I am in low revs and am getting the car moving in first gear. The pitch of the sound is not dependent on engine revs. It has gotten progressively louder in the past two weeks.
I've never heard of anything like this. Any idea what this could be?
Thanks.
Where does the sound come from?
I once had a similar problem with my '89 245. The sound came from the back and after searching some hours, a friend suggested that maybe two things touched each other. After some tries to increase the distance between the exhaust and the rear suspension, the sound even disappeared. Apparently, some part of the exhaust touched some part of the suspension system when the car started to drive.
But since such a sound is difficult to describe exactly, it may as well be something totally different... In my case, I heard the sound for about half a second to a second when the car started to move; louder if I accelerated faster, and when I accelerated very carefully, it even disappeared totally.
Groetjes,
Maarten
"But since such a sound is difficult to describe exactly, it may as well be something totally different... In my case, I heard the sound for about half a second to a second when the car started to move; louder if I accelerated faster, and when I accelerated very carefully, it even disappeared totally. "
Yes, that describes exactly the behavior of the sound in my car. However, I feel like mine is coming from the front.
Probably the heat shield on the headpipe is loose or cracked.
Bob
How are the engine mounts? The engine might be shifting and causing the fan or something else to rub.
Someone else suggested U-Joints... would failing U-joints cause this symptom?
Could be. U-joint noises often produce steady sounds, but they certainly experience the driveline torque and can respond to that. They are easy enough to check that it would probably be a mistake to overlook them. I've heard enough weird noises from U-joints that I don't doubt anything any more.
Mike
Does it happen _AS_ the clutch is being let out? If yes, then I would ask: Does it continue _after_ the clutch pedal is released completely?
If no, then it is probably either the clutch disc or the throwout bearing.
Can you make it happen without touching the clutch pedal (that is, if you allow the car to slow in first gear and then accelerate again, does the sound repeat as before)?
If yes, then it is probably some combination of one or more of:
1) Bad motor mounts or transmission mount. As they age they become soft and distort puttiong stress on the drivetrain. 2) A rattling heat shield on the exhaust manifold or above the catalytiuc convertor. 3) A rattling pre-heat tube off the heat riser on the exhaust manifold. 4) A rattling inner exhaust pipe on the header pipe. This pipe which riuns from teh exhaust manifold to the catalytic convertor is double walled and the insulation between them eventually breaks down and allows the inner pipe to vibrate. This can be loud. Mine vibrates at about 2000-2050 rpm (it's like having an audible tachometer). 5) bad alternator bearings, or bent alternator mount. 6) bad accessory mount bushings (alternator, power steering, or air conditioner compressor mounts). 7) broken, lose, or missing exhaust system mounts or clamps....should I keep going? ;-)
__ __ Randy & \ \/ /alerie's \__/olvos '90 245 Estate - '93 965 Estate "Shelby" & "Kate"
Failing U-joints tend to give you clunking when going from forward to reverse, and often vibrations at various speeds.
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