My coolint is evaperating,and i have to add every day

You must have a leak somewhere. Your coolant will not boil unless you have a leak. Check for leak traces of fluid the color of your anti-freeze. Your radiator cap is spring loaded and with time the spring gets weak.
Check that area for leak traces. The easiest way to check for leaks is to look at your driveway. if you have a coolant leak the fluid traces will be on the driveway. Don't mistake your air conditioner water leak as being the coolant fluid. The anti-freeze coolant has a sweet smell whereas the air conditioner fluid is just plain water being removed from the air inside of your cab.