Had a hard idle, shaking the car from steering wheel to tailpipe while at a stop and in gear. A bit smoother in neutral but still a little rough. I was suspecting a vaccum problem and was dreading the thought of tearing into those air hoses under the fuel distributor. I have a similar, but not as severe problem with my 2000 C280 so I guess I know what the problem is now.

I had changed the mounts once before at 135m, 12/2005. The old mounts were original to the car and lasted 14 years! The mounts I put in were ebay specials. Serves me right. The new ones I just put in appear to be quality German parts by Rein and were only a little bit more.

The right mount appears to have burst and the rubber was only about a third of the height of a new mount. The underside of the heat shield was coated with fine rubber particles. The left mount was about 1/2 height and had severe splits in the rubber.

The repair is relatively routine, the only difficult part is the top bolt for the left mount. Use a long 1/4" extension threaded from the top, just behind the EHA and a 17mm flex socket. It helps to have someone above holding the extension while you connect it to the socket you have on the bolt. It is pretty much a straight shot when you have the extension in the right hole.

My car with new motor mounts = wonderful again!

glenmore
1991 300CE
1999 C280
2000 C280
2000 C230K

I did the mounts on my 1990 300CE many years ago.
As I remember it was a pretty straightforward job.
I used MB mounts and the new ones were about 10mm thicker than the ones that I removed - due to colloapsing / aging.
I guess with aftermarket parts sometimes you get what you pay for !

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1990 300CE-24 (Gone but not forgotten)
2002 SLK 32 AMG
2002 ML320 (Gone)
1995 E320 Cabriolet