Lesson 5/Learning Event 1
Hot coolant is pumped out the top of the engine into the top radiator tank. It flows from the top tank through
the tubes in the core to the bottom tank. As the coolant makes its way down the tubes, it gives off heat to the
tubes. The heat is then transferred to the air fins and finally to cooling air as it passes between the fins. By
the time the coolant reaches the bottom radiator tank, it is cool enough to reuse in the engine. The coolant
pump draws the coolant from the bottom tank and forces it back into the engine.
A fan is used to draw air through the radiator core to speed up the cooling action of the radiator. The fan also
blows air on the engine to provide some direct air cooling of the engine. The fan is generally bolted to, and
turns with, the coolant pump shaft. In this way, the coolant pump and fan are driven by the same belt.