W201 chassis notes are in short supply, so here are my notes from a motor mount replacement:

The car is my early 85 190D. It has been reported elewhere that the drivers side motor mount rots from contact with fuel, and that was the case with mine. It looked thin, and the engine was clattery. So with new mount in hand, and after reading the forum on motor mounts--here is how it went.

1.) Jack up car from drivers side jackpoint. Do not work under car with screwjack. Use jack stands. Remove Drivers side front tire.

2.) Remove air filter cover and air filter.

3.) Remove belly pan.

4. Remove engine shock dampener from motor mounting arm. To do so, loosen the two small nuts (10mm socket) to either side of the shock from above, then loosen the same two nuts on the bottom end, and pull the shock out from underneath.

5.) From underneath the car, locate the access hole in the sub frame directly underneath the motor mount. Inspect the hex head bolt through this hole, and clean it out with a small screwdriver. Insert a 8mm hex head socket into this bolt. A light tap with a hammer seats the socket to the bolt, which is removed counterclockwise. In my case it was easy to turn. (So the engine has been out in recent years?)

6.) Place a block under the oil pan and a hydraulic jack, and lift the engine an inch or two. If you have a jackstand under the front jacking point, be aware that you can lift the car off the stand at this point.

7.) Wiggle the splash shield from the top of the motor mount out of the way and remove.

8.) This is the hard part: From the top of the engine compartment remove the two hex head cap screws that hold the mount to the subframe. The one on the outside is accessible from above with a set of long extentions. It is a 6mm hex head socket. Carefully clean out accumulated grit and seat the socket fully before starting to turn. Again in my case it was easy to turn out.

The back one is hard to find, hard to see and hard to remove, but the procedure is the same. In my case I used a T-40 Torx since the hex head was chewed up-- the Torx head works rather like a 12 point socket. You work from underneath the car to reach this cap screw.

9.) Remove the old mount. Jack up engine further if necessary.

10.) Clean up the subframe of old grime, and replace in reverse. I put the "good" cap screw in the back and the chewed up one in the front. If I werent 65 miles from a dealership I would have replaced these screws with new ones.

My motor mount had torn itself apart and was no longer working, so there was a lot of metal on metal damage to the old mount. Replacing it resulted in a quieter running engine. It also doesnt shake as much, which is good for everything. This job took me about four hours with one hour for the back bolt alone. On this car the passengers side mount looks a lot easier to reach, since its out in the open.