ThermoCap is equipped with a functioning reclamation valve. ThermoCap is compatible with a coolant overflow bottle.
When you know the coolant temerature, you can avoid getting burned. for example, if ThermoCap's meter indicates 235°, then it's better to leave the radiator cap in place. Run cool water over the radiator, and leave the engine running. If ThermoCap's meter indicates 145°, you could probably remove the cap to check the cooland level with reasonable safety.