Overheated and found that I had no coolant. Engine cool filled radiator and reservior to Max line with water. It has been insanely hot in California I might add. Drove home 90 miles and next day drove another 130. Found on way home slightly over heating, immediately turned off air and pulled off. Temp went down. Continued another 12 miles to home. Home found I had to add entire bottle of premixed coolant I had just bought. Reservoir was empty as well. Fan running, does not to appear have leaks. Any ideas?
Assuming you are asking why it nearly overheated again, there are a few possible reasons this could be.
- When you added from empty, there was some air stuck in the system. When it worked its way thru, you ended up with a low level again.
- There is a blockage in the cooling system that is causing it to not circulate.
- The coolant is leaking out.
- The radiator cap is bad, which allows the system to boil off.
You have left so much detail out, we can't answer with certainty. You need to monitor the coolant level. If it is still going down and there are no external leaks, there is likely a major problem with the engine.