Radiator Coolant Leak
 

Update: I followed everyone's advice, purchased the radiator fluid from Porsche and bought a new radiator cap, also bought a repair manual. In reading the first part of the manual I realize how sophisticated my 2003 Boxster S really is.

I started the procedure of fill the radiator researve back up and found it's a steady leak coming for the right central area of the engine.

Now I have to go about jacking up the car, which is a bit of a pain without damaging anything and finding out where the leak is.

I will report my findings and resolution.

This forum is a great help.