The radiator cap:

Question

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.

Accepted Answer

Should not be removed when the coolant is hot.

Answer

Can be removed when the coolant is hot.

Answer

Should be cool to the touch under normal driving conditions.