why is my coolant draining out?

[chamilka]

Car: 1997 Boxster 2.5 base. 95k miles.
Issue: When attempting to fill the expansion tank with coolant, it quickly drains out through the overflow hose.

Background: During an Autocross event today, I observed coolant leaking under the rear passenger wheel well after several hot sessions. Upon closer inspection, I noticed coolant also steaming off the rear trunk, originating from the expansion cap. The area beneath the expansion tank was also wet, and the coolant tank was nearly empty (95%).

I decided to tow the car back home and tried refilling the tank. However, as I filled the expansion tank, the coolant immediately drained through the overflow hose. I recall adding a small amount of coolant to the tank the day before, raising concerns about whether this contributed to the issue.
note: Two weeks earlier, I tracked the car at a local PCA DE event without encountering any problems.

Considering there had been a recall/upgrade for the tank and cap, I opted to order a new expansion tank kit from Pelican.
Do you think this was the right decision?

[78F350]

Do you think this was the right decision?

Yes. If they haven't been replaced already, they are certainly due.

[tonythetarga]

Agree also. It should only run out of the expansion tank if it overheats and boils over. If you’re just putting it in and it’s draining straight out it’s not the overflow tube.

[chamilka]

Thank you all. I will pressure test it this weekend to identify the exact issue, the parts should be here by then.

[Starter986]

Originally Posted by chamilka

Thank you all. I will pressure test it this weekend to identify the exact issue, the parts should be here by then.

Tell us you ordered the PORSCHE tank.

Tell us you didn't order the URO tank.

Tell us.

[lkchris]

By German law, all the plastic on this car is biodegradable. New expansion tank at 20 years for sure.