DIY: 190e 2.6 motor and transmission mount replacement (pics)
 

I did this over the weekend and figured I'd share in case someone else was considering doing this. Hopefully it will be of some help. Symptoms of failing motor mounts are vibration despite having the economy needle all the way to the left. I also was experiencing vibration when the car was in reverse especially when going up hills. Clearance is quite tight in the engine bay and while it doesn't require any special tools, I had to remove the airflow meter to get to the driver's side mount top bolt. Here's a brief run down of what I did:

1. Jack up car on jack stands, block wheels, and remove lower engine cover (8mm socket)
2. To allow radiator to tilt when the engine was raised, I disconnected the radiator support by removing the 7 bolts (10mm), the air scoop to the air cleaner (red arrows) and loosened the fan shroud
http://mypage.iu.edu/~plattd/w201/DSC_0003.jpg
3. Working from behind the first manifold, I used a shallow flexible socket (Snap On FUM17A) on a 10 inch extension to remove top bolt (17 mm).
http://mypage.iu.edu/~plattd/w201/DSC_0001.jpg
4. Working from below the car using a 8 mm hex socket I removed the bolt holding the lower mount. These were difficult to remove. I used a Hazet 916Lg fully extended (610 mm).
http://mypage.iu.edu/~plattd/w201/DSC_0002.jpg
5. Position the jack below the oil pan and jack the engine up. I used a jack with a rubber jack pad which worked well (AC-Hydraulic DK 20).
http://mypage.iu.edu/~plattd/w201/DSC_0004.jpg 6. Remove the mount and place new mount (note, you may have to jack the engine up more, if your mounts have collapsed like mine had)
7. Working from below, mount 8mm hex screw and tighten until snug.
8. Slowly lower engine on mount ensuring that the alignment pin is centered in groove between engine and engine mount
http://mypage.iu.edu/~plattd/w201/DSC_0008.jpg
9. Tighten bolts (55 newton meters upper, 40 newton meters lower)
10. Drivers side removal is more complicated. I couldn't get an extension through the manifold so I removed the mixture unit which I could use a standard socket (17mm) and a 10 inch extension to access the top bolt.
http://mypage.iu.edu/~plattd/w201/DSC_0005.jpg
11. Repeat steps 4-9 an you're done.

Transmission mounts
1. Jack up car on jack stands, block wheels
2. Support transmission with jack.
3. Remove 4 17 mm nuts on crossmember.
4. Remove 2 13 mm nuts on crossmember.
5. With jack lower transmission slightly.
6. Remove 19mm top nut using long pattern wrench (I used a Snap On XDHFM1719) I used PB blaster first on this bolt which made removal easier. It was a tight fit but I was able to fit the wrench in between the heat shield and the catalytic converter to get extra leverage. Remove bolt and mount.
7. Installation is reverse of removal (There a front a rear to the mount, the ridges go in the rear) Tighten bolts: 19mm to 70 nm, 17mm 40nm, and 13mm to 20nm. (note that this mount like the motor mounts has a proper orientation)
http://mypage.iu.edu/~plattd/w201/DSC_0007.jpg


Final notes
This job isn't that difficult provided you have the proper tools and plenty of time. Working slowly I did both jobs in about 6 hours. I also applied anti seize compound to all bolts making removal next time much easier. Good luck!

Nice write up!