Your engine cooling system is a vital part of your car. It ensures that the engine does not overheat and seize up, which can lead to costly repairs. The radiator's job is to cool down the hot liquid in your machine by transferring heat from the coolant fluid into the air passing through it. This process creates a vacuum effect that pulls more air past the fins and increases air circulation, which helps keep things running smoothly.
A radiator pressure cap (the little silver thingy on top of your radiator) helps regulate the system and provides an easy way for you to tell whether or not you need to add more coolant. When the liquid reaches a certain level by escaping through the cap, it triggers the vacuum effect and sucks in more liquid from the reservoir as it is being used up.
How to Tell If Your Car's Coolant is Low: Checking the pressure cap of a car's radiator reveals several important pieces of information: its current coolant level and its system pressure.