I had this happen to me and it got progressively worse to the point
that I was topping up a gallon of coolant after only a 5 mile run. I
could never see the source of the leak as it was right in the middle
of the engine.

It turned out to be a worn water pump bearing.

The sign will be if it gets  progressively worse over about 1-3 months.

Peter.

At 11:54 AM -0800 12/12/02, John Runberg wrote:
>Previously, I was leaking from the thermostat housing, and not that
>that's fixed I'm leaking from another place, this time in the far
>rear / center of the engine which only appears after the car has
>been sitting for about 8hrs. I'll notice it when I go out to go to
>work and when I look underneath there's collant on the rear engine
>cross bar. Looked from the top during lunch today and saw nothing
>too odd. I'll dig into it this weekend when I have some free time,
>but in the mean time, what are the likely culprits? Last time I'd
>begin to see the leak soon after shutting the van off, but this time
>is different. She runs fine and isn't overheating at all.
>
>TIA,
>
>john