We have a 2000 Boxster that has never given a moment of trouble.. Recently it started pushing out about 2 litres of coolant after a longer drive. Our local shop checked it out and the only thing they found was a minor leak in the coolant filling tank. We changed that and still have the exact same issue. My gut says thermostat, but even when driving it doesn't overheat, and only pushes the coolant out after shutting off the motor. Cooling fans are coming on, both from radiators where changed about 3-4 years ago.
Appreciate any ideas or suggestions.