My son's '86 has rather loud resonance that is coming off the exhaust system when the car is stopped in "drive" or "reverse". I noticed today that if I pry down on any portion of the exhaust from the front to the rear the noise stops. I have temporarily placed a small block of wood between the pipe and the body and this has stopped the vibration. All of the rubber mounts seem to be in place and the exhaust system seems to be intact. I have heard this same noise coming from several other 240s in parking lots and so this must be a typical bit of Brick character...however I am looking for a more permanent fix. Any suggestions as to what is at fault and how to fix would be appreciated.

Thanks to all in advance,

Cliff

Yeah I agree with Max, it's likely to be the heat shields. There are several, on both the front head pipe and the cat itself. All of them can be removed in a few minutes with a pry bar or big screwdriver. There really doesn't seem to be any penalty to doing this.
Every Volvo shop I've seen has a big pile of old shields out back in the scrap bin. The spot welds break so they're loose, but they're not smart enough to fall off by themselves.
Just snap the rest of the welds and they'll fall right off. Take that piece of wood out of there before it catches fire. That would be very disappointing. The surface of the catalytic converter can reach 750 degrees or more.

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Rob Bareiss, New London CT ::: '87 244DL/M47- 234K, '82 245T/M46-182K, '89 244DL/AW70- 212K Not too distant past: 86 244DL 215K, 87 244DL 239K, 88 744GLE 233K, 88 244GL 147K, 91 244 183K

Usually the heat shield covering the CAT is the main problem.. Just take a large aircraft hose clamp and tighten it around it,, works rater well.. But if you want a beter fix, have it welded or replaced.. but for my money the clamp is great.
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Max..1989 244 DL 5 Spd., Bilstein HD, Turbo Swaybars, Poly Bushings all round, Turbo Wheels, Black leather interior, Electric mirrors, LED dash and gauge lights.