Cooling System Flashcards
What is the purpose of the Cooling System?
To remove excess heat, maintain operating temperature, help the engine reach operating temperature quickly and operate the engine heater.
What is the typical operating temperature of an engine?
80 - 100 degrees Celsius
List Five reasons why it is important for the engine to warm up to operating temperature quickly.
- It minimises poor fuel vaporisation or combustion.
- Prevents part wear.
- Prevents oil contamination.
- Prevents reduced fuel economy.
- Prevents increased emissions.
What is the name of the water pump used on the cooling system and how does it work? 3 steps.
- The Impeller pump, powered by a ribbed belt, which is turned by the crankshaft, generates centrifugal force.
- This produces suction in the centre of the pump housing which throws coolant outwards.
- The coolant is then pushed around the cylinders, through the cylinder heads, through the thermostat and back into the radiator and the pump through the water jackets.
What are the Two types of cooling systems?
Air Cooling and Liquid Cooling.
Differentiate between Conventional Coolant Flow and Reverse Flow Cooling.
In conventional coolant flow, the hot coolant flows from the cylinder head to the radiator. After being cooled in the radiator, the coolant flows back into the engine block through the lower hose. In reverse flow cooling, cool coolant enters the cylinder head and hot coolant exits the block to return to the radiator. This helps keep a more uniform temperature throughout the engine and is usually found in high performance engines.
Why does the lower coolant hose have a spring in it?
To prevent collapsing under the suction of the water pump.
Which type of hose clamp is best to use?
Worm-drive clamp.
What are the two types of Radiators?
Downflow and Crossflow Radiators
What is the importance of the transmission oil cooler and where is it commonly located?
The transmission oil cooler is often placed in a small tank inside of one of the radiator tanks in cars with automatic transmissions. It prevents transmission fluid from overheating.
What are the Four main purposes of the Radiator Cap?
- It seals the radiator
- Pressurises the cooling system
- Relieves excess pressure from the cooling system
- Allows coolant flow between the radiator and the coolant reservoir.
If water boils at 100 degrees Celsius, how can the engine run at 100 degrees Celsius without the water turning to steam?
The Radiator Cap Pressure Valve maintains a certain level of pressure in the cooling system that helps in raising the boiling point of water.
What is the importance of the Thermostat in the cooling system and how does it work?
The thermostat senses coolant temperature and controls the flow of coolant through the radiator. It reduces coolant flow in a cold engine and increases coolant flow in a hot engine.
- In a cold engine, the wax filled pellet in the thermostat contracts and the spring holds the valve closed.
- In a hot engine, the wax filled pellet expands, the spring tension is overcome and the valve opens.
What is the name of the switch that turns on the radiator fans when the engine is warm?
Engine coolant fan switch.
What is the importance of antifreeze in the cooling system?
The Antifreeze prevents the freeze up of the engine during the season of winter, prevents rust and corrosion in the engine, lubricates the water pump and cools the engine.
