I have never seen a fluid filled motor mount, or any kind of hydraulically damped motor mounting system, but having just said that, there are small shocks that are part of the system that might be causing you to ask this question.
What specifically, is the problem, or root of this question?
"We drive into the future using only our rearview mirror."
- Marshall McLuhan -
Northern California Wine Country...
"Turbos whistle, grapes wine..."