Coolant leak hint?

[Bradster]

Just as I was pulling into my driveway this morning my 97 started making a loud groaning noise under load. After I pulled into my driveway I noticed that coolant was leaking from the bottom of the car towards the middle near a radiator hose connection. Steam was coming from the right, passenger side engine grill. As I was jacking up the car to find more clues, the leak stopped. In other words, once the expansion tank was emptied, there was no more leak.

Before I start pulling things apart, does that mean that it must be the expansion tank, or could it be the water pump? What I mean by that is if it was the water pump, would some five gallons of fluid leaked or once the coolant reached a level below the pump, the leak would stop. I assume if it was a bottom radiator hose most or all of the fluid would have leaked. In my Bentley, I did not see instructions on the expansion tank removal and replacement.

Anyway, that's what I know at the moment.

As always, thanks folks!