Engines - Cooling Systems and Air Conditioning

Question 1

Name a component used to improve outside air cooling

Answer 1

Cooling fins

Question 2

Give 2 advantages of air cooling

Answer 2

Less engine maintenance
Shorter warm-up period

Question 3

Where does the air come from in outside air cooling?
Where does the air come from in forced air cooling?

Answer 3

Air from outside the car enters to cooling system when the car is moving
Air is blown in by a fan, which still produces airflow when the car is stationary

Question 4

Where is the oil cooler mounted?
What is its purpose?

Answer 4

Mounted completely in the outside air flow
To cool the oil so that it does not lose its lubricating properties

Question 5

By how many degrees is oil cooled by outside air flow?

Answer 5

25 to 50 degrees C

Question 6

Which kinds of cooling are direct and which are indirect:
Outside air cooling
Forced air cooling
Oil cooling
Liquid cooling

Answer 6

Direct
Direct
Indirect
Indirect

Question 7

List 3 advantages of liquid cooling

Answer 7

Engine cools more uniformly
Less engine noise
Engine remains at temperature for longer, so that it can get started more quickly after a pause in driving

Question 8

List the main 5 components of a liquid cooling system

Answer 8

Coolant pump
Thermostat
Fan
Radiator
Pressure cap

Question 9

What is the function of a thermostat in a liquid cooling system

Answer 9

Controls the flow of coolant through the radiator

Question 10

What is the purpose of the pressure cap in a liquid cooling system?

Answer 10

To increase the pressure and therefore increase the boiling point of the coolant

Question 11

What will dashboard signals inform you about in terms of the coolant?

Answer 11

Coolant temperature
Coolant level

Question 12

What is a thermostat referred to as if it only operates on one valve? What about if it operates on two?

Answer 12

A single-action thermostat
A double-action thermostat

Question 13

How does a thermostat operate?

Answer 13

Wax, which expands as it heats up

Question 14

Where is the pressure cap usually located? What does it do?

Answer 14

On the expansion tank or the radiator
Raises the boiling point of coolant

Question 15

What should you never do with a pressure cap? Why?

Answer 15

Take it off while still hot
The water can boil immediately and shoot into your face

Question 16

What 2 valves can be found inside a pressure cap?

Answer 16

Vacuum valve
Relief valve

Question 17

What do you use an anti-freeze gauge for? How to you use one? (in 4 steps)

Answer 17

Determine the freezing point
Open the glass gauge cover
Drop a tiny bit of coolant onto the plate under the over
Press the cover back down
Put it to your eye and look at the reading

Question 18

In coolant freezes, what components can it cause to crack?

Answer 18

Engine block
Cylinder head
Radiator
Coolant hoses

Question 19

What is the optimum temperature for an engine called?

Answer 19

Operating temperature

Question 20

The engine dissipates its heat through the cylinder wall. Where does this heat go?

Answer 20

The coolant

Question 21

How does the heated coolant transfer its heat to the outside air?

Answer 21

Via the radiator

Question 22

List 3 symptoms of insufficient coolant

Answer 22

Overheated engine
Uncontrolled combustion
Poor lubrication

Question 23

List 3 symptoms of excessive coolant

Answer 23

High fuel consumption
Internal engine contamination
Condensation of fuel droplets

Question 24

List 2 functions of the expansion tank

Answer 24

Provide coolant when there is a shortage
Store excess coolant

Question 25

Can the expansion tank be connected to the cooling system by systems where the coolant does flow through the expansion tank or systems where it doesn't flow through the expansion tank?

Answer 25

Both

Question 26

What 2 things happen in a cold expansion tank when the temperature rises? What will happen when it lowers back down (other than the reverse of when it goes up)?

Answer 26

The excess pressure valve on the pressure cap opens The coolant flows into the expansion tank The vacuum valve on the pressure cap opens

Question 27

What is a cooling system referred to as if the coolant does not flow through the expansion tank? What about when it does?

Answer 27

Cooling system with a cold expansion tank Cooling system with a hot expansion tank

Question 28

What is the main feature of a cold expansion tank that is different to hot, in terms of process

Answer 28

The pressure cap always remains closed

Question 29

Where is a hot expansion tank positioned? Why?

Answer 29

Above the radiator So that the radiator is always full of coolant

Question 30

What is the purpose of a radiator?

Answer 30

To dissipate heat from the coolant to the outside air

Question 31

What is the radiator core usually made of? What about the water tanks?

Answer 31

Aluminium Plastic

Question 32

What are the main 2 components of the radiator core mesh?

Answer 32

Small pipes Cooling fins

Question 33

Why do radiator cores have cooling fins?

Answer 33

To increase the cooling surface area

Question 34

Name the 2 main types of radiator

Answer 34

Crossflow Downflow

Question 35

Other than the water flowing down, list 2 ways to know if a radiator is downflow

Answer 35

The water tanks are on the top and bottom There is a filler cap

Question 36

Other than the water flowing from right to left or lefft to right, list 2 ways to know if a radiator is crossflow

Answer 36

The water tanks are on the left and right The filler cap is on the expansion tank, no the radiator

Question 37

Why are crossflow radiators used more in modern cars?

Answer 37

Smaller height

Question 38

What is the main difference between an electric thermostat and a mechanical one?

Answer 38

The electric thermostat has a filament in the wax

Question 39

Give one advantage of using an electric thermostat over a mechanical one

Answer 39

Can respond more effectively to different operating situations

Question 40

What happens to refrigerant when it flows through the evaporator?

Answer 40

It turns from liquid to gas

Question 41

What happens to refrigerant when it flows through the evaporator and the outside temperature is very low? (3 things)

Answer 41

Not all of it turns to gas A little liquid refrigerant leaves the evaporator The compressor is fed with liquid refrigerant

Question 42

What happens to refrigerant when it flows through the evaporator and the outside temperature is very high?

Answer 42

A little liquid refrigerant leaves the evaporator

Question 43

What happens if a little liquid refrigerant leaves the evaporator and is therefore fed to the compressor?

Answer 43

The compressor is damaged, because it cannot compress a liquid

Question 44

What does the accumulator do?

Answer 44

Collects the unevaporated liquid refrigerant that otherwise would flow to the compressor and damage it

Question 45

What kind of orifice always lets through the same amount of refrigerant?

Answer 45

Fixed orifice

Question 46

What can be used instead of a fixed orifice, which reduces the chance of liquid getting to the compressor?

Answer 46

An expansion valve

Question 47

Where in the system would the accumulator be put in comparison to the fixed orifice? What about the filter dryer in comparison to the expansion valve?

Answer 47

After Before

Question 48

List 2 components which are specific to a non-regulated air conditioning system

Answer 48

Accumulator Fixed orifice

Question 49

List 2 components which are specific to a controlled air conditioning system

Answer 49

Filter dryer Expansion valve

Question 50

Where is the condenser located? Why?

Answer 50

In the front centre of the engine compartment To maximise airflow through it

Question 51

Where are the evaporator and expansion valve located?

Answer 51

In the back of the engine compartment, behind the bulkhead

Question 52

What is the bulkhead?

Answer 52

The panel that separates the engine compartment from the passenger compartment of a vehicle

Question 53

How does an internal combustion engine drive the air conditioning?

Answer 53

Using a belt

Question 54

List the 4 main components of the air conditioning system

Answer 54

The evaporator The valve (can be an expansion valve or fixed orifice) The compressor The condenser

Question 55

Which of the 4 main component of the air conditioning system does the refrigerant flow through?

Answer 55

All of them

Question 56

What 2 things happen to the refrigerant when the temperature drops?

Answer 56

The pressure of the refrigerant remains the same The temperature of the refrigerant drops

Question 57

In what state is the refrigerant when it leaves the condenser?

Answer 57

Liquid