A water pump is a simple device that will keep the coolant moving as long as the engine is running. It is usually mounted on the front of the engine and turns whenever the engine is running.
The thermostat is simply a valve that measures the temperature of the coolant and, if it is hot enough, opens to allow the coolant to flow through the radiator.
If the coolant is not hot enough, the flow to the radiator is blocked and fluid is directed to a bypass system that allows the coolant to return directly back to the engine.
This is a passage that allows the coolant to bypass the radiator and return directly back to the engine.
The radiator core is usually made of flattened aluminum tubes with aluminum strips that zigzag between the tubes.
These fins transfer the heat in the tubes into the air stream to be carried away from the vehicle.
On each end of the radiator core is a tank, usually made of plastic that covers the ends of the radiator,
The hot coolant is also used to provide heat to the interior of the vehicle when needed. Like when your cold and turn the heat on.
There are several rubber hoses that make up the plumbing to connect the components of the cooling system. The main hoses are called the upper and lower radiator hoses. These two hoses are approximately 2 inches in diameter and direct coolant between the engine and the radiator. Two additional hoses, called heater hoses, supply hot coolant from the engine to the heater core. These hoses are approximately 1 inch in diameter.
Mounted on the back of the radiator on the side closest to the engine is one or two electric fans inside a housing that is designed to protect fingers and to direct the air flow.
These fans are there to keep the air flow going through the radiator while the vehicle is going slow or is stopped with the engine running. If these fans stopped working, every time you came to a stop, the engine temperature would begin rising.