My car has recently developed an exhaust vibration. It is only felt when accelerating lightly. Seems fine at idle and under hard acceleration.

The car has 200k. I haven't yet jacked it and looked underneath. I have discovered 2 items:

1. The upper mount has one small visible crack in it.
2. The rear of the exhaust shifted up and burned the bottom of the plastic bumper. I replaced the rear exhaust mount/bracket a couple of years ago with the IPD one. It looks okay. I just sprayed the bolt with PB Blaster a couple of days ago (it wouldn't budge) and will attempt to adjust the bracket ASAP.

So it appears as if I need a new upper mount at a minimum. 2 quick questions:

1. Is there anything else I should be checking out or part I might need?
2. Would a bad mount allow the exhaust shift up like it has?

Thanks for any help!
Jim

If the exhaust tip touches the plastic, that is probably the cause of the vibration. But, the exhaust tip should never get that hot. At least the way I drive.

Yes, the upper mount will change the exhaust pipe orientation upward when accellerating. A hard push on the throttle will cause the tip to be in constant contact with the bumper, so no vibration. Idle is the opposite, no pressure.

A cracked upper mount is a failed mount, it does need replacing. Don't forget to check the lower front mount under the crank pulley as it is also subject to failure.
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My name is Klaus and I am a V♂lv♂holic

Thanks, Klaus!

The exhaust pipe not only burned the bottom of the bumper it melted it...:) A couple of weeks ago I did 4 hour highway trip to N.H. and that's when I discovered I had a problem. Later I found the crack in the upper mount. So what you said about accelerating makes sense since I was driving 70-75 mph for the entire trip and that must have really heated things up!

Yesterday I did look at the lower front mount. Didn't see any tears or cracks. Put a pry bar on the engine and it did move a little. A little movement is normal, right? It is a Volvo mount so I assume it is the original. Should I consider replacing it even if it is still good?

My front mount lasted about 150K miles, but that will depend on potholes and other rough road items.

The rounded part of the rear bumper cover can be replaced. I suggest looking at a junk yard for the correct color. Or, they are fairly cheap at the dealer but unpainted.

BTW, the exhaust pipe should have about 1 inch clearance all around when the engine is off.
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My name is Klaus and I am a V♂lv♂holic