Front Engine Mount Question

[saint_ex]

I recently replaced my Fr engine mount, and, just for fun, I decided to see what's inside of it. Using a knife, I made a hole in the rubber cover at the bottom of the mount. Some kind of liquid came out...it looked like engine oil. Does anybody know whether this is normal? I was under the impression that it is vacuum driven, i.e. that there should be no liquids in it.

How does this vacuum-driven mount actually work, anyways?

Thanks!

[Toysrme]

Yes, it is an oil filled mount.