I'd suspect a loose connection. Lower the head as far as possible, and get yourself up on top for a look. The coolant tube emanates from the Z axis flex conduit, so that is where you can start looking for leaks and test the connections with a pair of wrenches. It may be necessary to remove the front and side covers to get at a lower leak.
First you get good, then you get fast. Then grouchiness sets in.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)