Deck 3: Engine Cooling and Comfort Heating Systemsdiagnosis and Service of Engine Cooling and Comfort Heating Systems

Question 1

All of the follow are true about engine thermostats EXCEPT:

A) A thermostat may be removed from a system if it is running hot.
B) A faulty thermostat will effect vehicle emissions.
C) A stuck closed thermostat will cause engine overheating.
D) A stuck open thermostat will cause engine overcooling.

Answer 1

A

Question 2

Technician A says a defective radiator cap vacuum valve may cause hoses to collapse.Technician B says a defective pressure valve may cause coolant boil over and loss.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Answer 2

C

Question 3

To safeguard other cooling system components,a defective pressure cap should be replaced with one having a lower pressure rating.

Answer 3

False

Question 4

It is okay to mix standard ethylene glycol in a cooling system containing extended life coolant; it will not affect the corrosion protection rating.

Question 5

All of the following statements about engine cooling are true,EXCEPT:

A) Engine heat is transferred to the coolant.
B) Coolant heat is transferred to the ambient air.
C) Heat transfer is through conduction and radiation.
D) Much of the heat generated in the engine leaves through the exhaust system.

Question 6

If coolant in not reused,it must be disposed of or recycled in an environmentally safe manner.

Question 7

The temperature rating marked on a thermostat is the temperature at which it begins to open.

Question 8

Coolant pump leaks are often caused by worn bearings.

Question 9

A thermostat is not needed if the vehicle is only driven for short distances.

Question 10

The two basic design types of radiators are

A) down flow and cross flow.
B) up flow and down flow.
C) cross flow and recirculating flow.
D) up flow and cross flow.

Question 11

All of the following conditions could cause poor passenger compartment heating system performance EXCEPT:

A) An air pocket in the heater core.
B) Thermostat stuck in the closed position.
C) A heater control valve stuck in the closed position.
D) A restricted heater core.

Question 12

A vehicle in for repair has a burst upper radiator tank.Technician A says thermostat htat was stuck in the open position could be the cause.Technician B says that a faulty radiator pressure cap could be the cause.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 13

The engine cooling system is designed to remove about 80 percent of the total engine heat.

Question 14

Technician A says that serpentine belts made of EPDM resist cracking and instead exhibit wear to the belt ribs similar to tire wear and that a depth gauge should be used to assess belt wear.Technician B says that as a neoprene serpentine belt ages and wears that cracks will form on the belt ribs and that if there are more than 3 cracks in a 3 inch span the belt should be replaced.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 15

After a vehicle has been driven for 10-15 miles,the heater still continues to blow cool air.Which of the following is the most likely cause?

A) Faulty water pump impellers.
B) Partially blocked radiator.
C) Thermostat stuck closed.
D) Partially blocked heater core.

Question 16

Some radiator fan motors will start and run without warning.

Question 17

The most common cooling system problems are the result of leaks.

Question 18

If a thermostat fails in the open position,all of the following will occur,EXCEPT:

A) longer than normal warm-up period.
B) poor heater performance.
C) loss of coolant.
D) erratic computer control system operation.

Question 19

Technician A says excessive engine heat is a product of combustion.Technician B says the average automotive engine is only 15 percent efficient.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 20

Thermostats open and close gradually as the temperature of the coolant increases or decreases.

Question 21

Technician A says the cooling system must be full for a pressure test to be effective.Technician B says the cooling system should never be pressurized beyond the pressure cap rating.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 22

Technician A says the radiator outlet is connected to the water pump inlet by a rubber hose.Technician B says the thermostat is usually located at the engine coolant outlet.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 23

Engine coolant is designed to provide all of the following EXCEPT:

A) Lower the freezing temperature of the solution.
B) Inhibit rust and corrosion.
C) Provide water pump lubrication.
D) Lower the boiling point of the solution.

Question 24

Which of the following could cause symptoms of overcooling even though the engine temperature is normal?

A) a defective temperature sending unit
B) a missing thermostat
C) a defective thermostat
D) all of the above

Question 25

Technician A says one should always follow OEM specifications for a radiator pressure cap rating.Technician B says a defective radiator pressure cap could cause overcooling.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 26

Engine overcooling is being discussed: Technician A says that a missing thermostat could be the cause of this condition.Technician B says that a thermostat stuck open could be the cause of this condition.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 27

All of the following conditions could cause an engine coolant loss,EXCEPT:

A) leaking engine head gasket.
B) leaking transmission cooler lines.
C) faulty radiator pressure cap.
D) leaking transmission oil cooler.

Question 28

An engine coolant temperature switch or air conditioner select switch is used to energize the

A) blower motor.
B) radiator fan motor relay.
C) compressor clutch.
D) dashboard warning light.

Question 29

Caustic cleaning solutions should not be used in ____ radiators.

A) aluminum
B) copper
C) plastic
D) any

Question 30

Technician A says the primary purpose of a thermostat is to cause the engine to warm up as soon as possible.Technician B says the thermostat should be removed from the cooling system only if the engine is overheating.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 31

During a routine fluid level inspection a radiator is found to be low on coolant,but the coolant recovery tank was at the proper level.Technician A says that a faulty radiator cap could be the cause.Technician B says that a cracked radiator to recovery tank hose could be the cause.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 32

If a thermostat fails in the open position,all of the following will occur,EXCEPT:

A) A loss of engine coolant.
B) A longer than normal warm-up period.
C) Poor heater performance.
D) A vehicle may fail emissions test.

Question 33

Why do inlet radiator hoses (lower)usually have a spiral steel wire molded into them?

Question 34

Explain the most obvious signs of leaks in a heater core.

Question 35

A thermostat in the cooling system helps prevent

A) overheating.
B) overcooling.
C) rust formation.
D) heater core leaks.

Question 36

All of the following statements about engine cooling systems are true EXCEPT:

A) Electric cooling fans may turn on even when an engine is not running.
B) Extended life coolant is rated to last in excess of 100k miles.
C) Extended life coolant and standard life coolant are both ethylene glycol based.
D) It is ok for a technician to install a thermostat with a low temperature rating than the original thermostat.

Question 37

Technician A says an ethylene glycol and water mixture lowers the freezing point of the coolant.Technician B says an ethylene glycol and water mixture raises the boiling point of the coolant.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 38

A vehicle is in for service with a complaint of poor heat output.The technician finds air trapped in the heater core.What is the most likely cause of this condition?

A) A faulty radiator pressure cap.
B) A leaking cyclinder head gasket.
C) Worn water pump impeller blade.
D) A stuck open engine thermostat.

Question 39

A vehicles engine temperature gauge is reading higher than normal and the readiator fan does not operate.Technician A says that no continuity across the fan motor could be the cause.Technician B says that an open radiator fan fuse could be the cause.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 40

Technician A says a 70-30 mixture of water and ethylene glycol is the best coolant formula for most engines.Technician B says a 50-50 mixture of water and ethylene glycol is the best coolant formula for most engines.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 41

Explain the operation of the radiator cap pressure and vacuum valves.

Question 42

What inputs may the PCM look at to determine the need to engage the cooling fan?

Question 43

Name two common radiator core designs.

Question 44

What can cause overcooling?

Question 45

What is the purpose of the automotive cooling system?

Question 46

Many electric cooling fans are ultimately controlled by what device?

Question 47

What is the purpose of a heater core control valve?

Question 48

What are the requirements when a pressure cap is tested using a cooling system pressure tester?

Question 49

What are the major components of the cooling system?

Question 50

What is the purpose of the overflow tank?

Question 51

What are the advantages of engine temperature being adjusted to current operating demands on the electronically controlled cooling system?

Question 52

Name the common engine antifreezes in use today.

Question 53

Why is it important to have a good engine coolant fan at idle and low speeds?

Question 54

What is the difference between the vertical flow and cross flow radiators?

Question 55

List common cooling fan designs used.

Question 56

List and explain the purpose of the components of a water pump.

Question 57

What is a PTC heater and on what vehicles can it be found?