Just curious. Why is the coolant pump called a "water" pump?
If there is a little bit of green fluid underneath the engine, is this a coolant leak?

 

1)I believe that started back when water was the coolant used and stuck. If you think about it this way coolant in your cars cooling system is a mixture of coolant/anit freeze and water. Glycol and such anti freeze does not have much of a heat absorbtion or the ability to disipate the heat as well as water this is the primary reason water is mixed with coolant.

2) Green fluid under a vechile would be glycol based antifreeze and for it to be on the ground under a car would be a sign of such things as a leak,over filling, or a leaky fitting ect.....