So as I was putting my CRD back together (it's only taken 20 months at this point), I decided I'd change the engine mounts. Sure enough, my engine is now sitting about 2 inches higher than it it used to.
When I got the without the heatshield out, I noticed that it was rattling. I had to know what was going on inside. I was aware it was filled with oil, but I decided to cut it open anyway.
The inside is looks something like this:
Note the bolt and the rubber cup. When I cut mine apart, the bolt wasn't in place. Beats the hell out of me how the bolt would have worked its way loose in a sealed engine mount, but if you look at the close up of the cup you can see scars on the metal of the cup, which I believe is from the bolt bouncing around inside.
[Note: please ignore the metal shavings, those are from cutting the thing open.]
So, if you always wanted to know what one looked like on the inside . . . now you do.
[Edited so that photos actually show up . . .]