Today's trackday was a bit of a disaster. Hot day - 30C. After 15 minutes on the track the engine severely overheated - I first noticed that the autobox was blinking an error code at me, then my gaze shifted to a check engine light, finally to the temperature indicator hovering as high as it can go above the H mark. Snap. Return to pits, asess damage. And the day barely started!
First thing I noticed - the overflow reservoir was empty, I put some coolant in it but it started doing something which didn't strike me as normal. See video, with engine off:
So I let the car sit for 15 minutes to cool down so that I can check the radiator cap - unscrewed it and saw... a dry radiator. Snap. Snap. Then I notice a spring lying on top of radiator, and the fact that the radiator cap was missing parts. Triple Snap.
So I found a new cap - 1.1bar, refilled system and drove on. But still I was getting the occasional spikes in temperature. Not "H" level though, but half way, at which point I was making cooling laps.
What I am guessing has happened is that the system got up to temperature and pressure, and the radiator cap broke down due to age. Then coolant got pushed out... Not sure how all of it managed to escape though? I think I used 5-6l of coolant to refill the system at a gas station.