OK so this was posted by other people here and i have now the same exact issue,

driving home today like usual, hot day, the "coolant low stop car" message comes on

i stop and see the coolant bottle is almost empty withg some of the fluid bubbling kinda at the bottom of the tank. some of the fluid came out through the cap which seemed to have come off with pressure i guess, i noticed a crack in the green part of the cap but it did not look major., at home i topped up the fluid and put another cap on the coolant tank that i had left over from another repair. drove around for about 15 minutes and everything was normal

Could a bad tank cap cause this ? i have my doubts so i think the problem will come back,, water pump failing? never had that happen so dont know the symptoms, temp gauge was always showing proper temperature so i dont think its the thermostat
can anyone help please

 

well, to those who care, i think this was caused by a bad cap on the coolant tank,,,since i replaced it last night and drove around today i have put on about 100KM and nothing happened, lesson: inspect your coolant bottle cap for cracks and maybe even keep one handy like i did ...

 

Thank you for your kind info andrei3333

 

Im having the same symptoms. Swapped out the Radiator, the neck on the old Rad came off in my hand (lol), sure got my $ worth of that one. Bought a new cap today (10 valve 850) and Thermostat. Old cap was black, this one is green... told that this is 'the' right one for me. Hope this fixes my problems, will update.