2002 Boxster coolant mystery...

[roland3337]

I have a 2002 Boxster (non-S) and I have something of a mystery on my hands with the coolant system (I think).

Had it out for a drive, and stopped for a beverage. I was away from the car for maybe 3-5 minutes. And while driving, I don't think the red indicator light was blinking. When I came back out to the parking lot, there was a large puddle of coolant on the ground. I don't know if it had been leaking while driving up to the moment I parked it or not. Drove it 2-3 more blocks, then called for a tow. Another large puddle appeared while waiting.

When I got it home, I filled up with more coolant and distilled water, started it up and waited for it to get to normal operating temperature. I was watching for leaks the whole time while waiting, but none appeared. The temperature went up a bit more, then the red warning light started blinking. I shut it down, but I still never saw a leak. I know that the expansion tanks on these cars is known to get old and crack, but that does not seem to be the case, since I did not see any leaks.

Any guesses about what was happening?

Thanks in advance. You guys have saved me thousands of $$$ over the years.