6 – COOLING SYSTEM
85
Piston Engine Fundamentals
TC010-05-01S
Water Pump
The water pump circulates coolant throughout the cooling system.
Coolant Passages
Coolant passages are cast into the cylinder block and cylinder head.
These passages carry coolant around the cylinders and combustion
chambers. The coolant picks up heat and carries it away from these
parts.
Thermostat
The thermostat regulates engine temperature by controlling the flow of
coolant until a certain preset temperature is met. This helps the engine
warm up quickly and maintain a more even temperature.
Radiator Reservoir
As coolant becomes hot, it expands. The coolant recovery system
stores the excess coolant released from the radiator. When the engine
cools, the coolant in the reservoir is drawn back into the cooling system.
This keeps the cooling system constantly full, increasing cooling system
efficiency.
Fan
The radiator fan pulls cool outside air over the radiator surface to pick
up heat from the coolant for faster heat transfer, especially during idling.
Models equipped with air conditioning usually have an additional fan for
increased cooling.
Pressure Cap
The pressure cap maintains pressure in the system which raises the
boiling temperature of the coolant, preventing the coolant from
evaporating or boiling off. This cap also allows excess pressure to
escape from the system.
Radiator
The radiator transfers heat from the coolant to the outside air. The
radiator core contains tubes and fins. Coolant flows through the tubes,
and the fins increase the radiator’s surface area exposed to the air. This
allows the air to carry away more heat, reducing the coolant
temperature.
Answers to Review
Exercise 7
1. oil strainer
2. main gallery
3. oil pan
4. rotor or trochoid
5. oil filter
6. B & D