The most common scenario is that the replacement parts are Swedish aftermarket ones, not German aftermarket ones.

The German ones are really soft, and are more like the original equipment mounts. They allow the engine to move quite a bit, not only side to side, but they absorb a tremendous amount of vibration.

The Swedish mounts are very hard rubber, and absorb little vibration. Also, they let the engine move around very little, which in my opinion gives the car a MUCH tighter feel. The downside of these mounts is that there is a pronounced vibration through the body at idle.

The vibration is part of the B230F. They aren't very smooth engines unless you muffle the vibration with old soggy mounts. Even in the 700/900 series cars they can show up with engine vibration. Even with new hydraulic mounts.

If the vibration is such that it is alarming, then there is something wrong. Perhaps a failed transmission mount (which should always be replaced along with the engine mounts especially for the little added expense, and short amount of time to change it) could be the issue. That can cause a lot of problems as well. When I speak of alarming, I mean not just a vibration that wasn't present before, but actually enough to rattle the whole car. Some amount of idle vibration is not unusual. It might be worth checking up on, just to make sure that everything is OK. But I suspect that it is.

Also, if the idle speed is a little sluggish, it could affect it that way. Try stepping on the gas JUST A TINY BIT when the car is at idle, in gear. If it goes away, you might have found the solution to the problem.
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1992 940 wagon, low miles
as well as others.