Would a coolant overflow valve dump the whole tank?

[ppbon]

Originally Posted by tommy986

I just had a similar experience. I live in an area about 200 feet above sea level. Drove to Salt Lake City with altitudes reaching 7000 feet, also outside temps in the 100+ range. On third day driving home through Texas, noticed the expansion tank was empty. Topped off and drove another 500 miles and its still full.
Where would the discharge go normally? There is some residue in the trunk which makes me think there may still be a leak. Also found some residue under the car.

... in the trunk, your coolant reservoir is most likely cracked.
Here are the replacement instructions:
Replace Coolant Reservoir

Happy Boxstering,
Pedro