It has nothing to do with your Head Gasket.
It sounds like a Bad Thermostat because when it dies it sticks open. So the car takes a long time to heat up, and often the Air won't get as warm because the Radiator is cooling off the air too fast.
You wouldn't be losing water because of a bad thermostat because it's stuck open your car is running cooler than it normally would.
You have probally overfilled it too many times and now you've got air bubbles in your system.
Take the Cap off and let the car idle for like 20 minutes. fill as needed.
Once all the air is out, put the cap back on and fill the overflow tank.
DON'T ADD ANY MORE WATER.
If you keep adding more, it'll keep spitting it out.
|