Before you start the test, please answer the question below regarding your insurance status.
Without insurance you will not be able to drive in Washington
Do you currently have car insurance?
The radiator cap:
Never remove the radiator cap or any part of the pressurized cooling system until it has cooled. Opening the cap while the system is too hot could release steam and boiling water that could severely burn you. If the radiator cap is cool to the touch, the system is likely cool enough for you to open the cap.