A radiator in your house is designed to keep the room warm, so many people assume it does the same thing in a car. In fact, it does the opposite; it cools the engine down.
Your car’s engine will heat up to a ridiculous temperature. And by ridiculous we mean somewhere in the region of 2,500 degrees Celsius. At these kind of temperatures the metal in the engine can weld itself together. If this happens, total engine failure is any moment away, and a costly repair bill isn’t far behind.
The heat comes from the friction between all the moving parts. We can to minimise this friction with motor oil which is pumped through the engine, acting as a lubricant, but it’s not enough to stop your car from melting. There’s still plenty of heat there to weld the engine together, and this is where the radiator comes in. A mixture of anti-freeze and water is pumped through the engine, sucking up all the excess heat produced by the all those moving parts spinning away.
This super-heated engine coolant goes through the engine, comes out the other side, and then into the radiator. The radiator is designed to have the largest surface area possible in order to let the heat dissipate. Some radiators have fans that bring cooler air from outside into the car and help the radiator with the process. The car’s grille is also designed for this purpose. With the outside air and the radiator bringing the coolant temperature down, the mixture is now cool enough to go back into the engine.
If you’re coolant is running out, or your radiator isn’t doing its job properly, then this could be a serious problem. Your engine will continue to heat up, getting hotter and hotter until it blows a piston or literally melts, welding itself together. This is why you should always check your radiator and oil levels on a regular basis- a quick check every couple of months can save you a lot of grief down the line. Radiators don’t have to particularly cool to work, but if they leak or crack, then it can only be a matter of minutes before the engine reaches critical levels. Always allow the engine too cool down before trying to bring it to a mechanics.