Deck 8: Compressors and Clutches

Question 1

There are signs of oil spray on the compressor clutch hub and nearby underhood areas.Technician A says that a faulty compressor clutch bearing could be the cause.Technician B says that a leaking compressor shaft seal 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

Answer 1

B

Question 2

A defective bearing may be hammered out of the compressor clutch housing.

Answer 2

False

Question 3

Technician A says most compressor clutches are driven from the engine crankshaft by a belt.Technician B says late model hybrid electric vehicles use an integrated electric motor to drive the compressor.Who is correct?

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

Answer 3

C

Question 4

Compressor clutch controls are being discussed.Technician A says a clutch may be cycled on and off based on system pressure.Technician B says some clutches will not be cycled on-off unless the driver operates the manual air conditioning control device.Who is correct?

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

Question 5

When the A/C switch is in the off position on a vehicle with a cycling clutch type system the compressor clutch stays engaged.Which of the following is the most likely cause?

A) The air gap for the A/C clutch is too great.
B) The compressor clutch relay is stuck closed.
C) The pressure switch is stuck closed.
D) The refrigerant system is overcharged.

Question 6

Liquid refrigerant may cause severe damage to the compressor.

Question 7

The most common type of compressors used on todays vehicles is the cam lock design.

Question 8

Some compressor noise is normal during regular operation.

Question 9

Snap rings may be installed backward to increase their holding power.

Question 10

The basic purpose of reciprocating piston,scroll,and rotary vane compressors is the same.

Question 11

If a bearing shows signs of excessive noise,binding,or looseness,it should be regreased.

Question 12

Turning the compressor axial plate has the same effect on the pistons as turning a crankshaft.

Question 13

All of the following statements about variable displacement compressors are true,EXCEPT:

A) Variable displacement compressor piston stroke is adjusted by an internal pressure valve.
B) Variable displacement compressors do not have a cycling clutch.
C) Variable displacement compressors have a cycling clutch..
D) Variable displacement compressors control evaporator pressure by varying their pumping capacity.

Question 14

Technician A says a wobble plate moves some compressors' pistons.Technician B says some swashplate compressors have double-ended pistons.Who is correct?

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

Question 15

Compressor clutch controls are being discussed.Technician A says a clutch may be cycled on and off based on system pressure.Technician B says some clutches will not be cycled on-off unless the driver operates the manual air conditioning control device.Who is correct?

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

Question 16

The compressor pumps refrigerant as a

A) liquid.
B) vapor.
C) liquid that changes to a vapor.
D) vapor that changes to a liquid.

Question 17

The compressor clutch circuit is being tested.Technician A says if the test lamp does not light when connected across the clutch's harness terminals,then the problem is probably a shorted clutch coil.Technician B says a test lamp that flickers or goes out may indicate the PCM or other control device is defective.Who is correct?

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

Question 18

Technician A says a compressor clutch may be cycled based on refrigerant (evaporator)temperature.Technician B says the compressor clutch may be cycled based on refrigerant pressure.Who is correct?

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

Question 19

Compressor oil level should be checked routinely.

Question 20

Broken compressor discharge valves are a rare defect.

Question 21

Technician A says some compressor service procedures can be performed on the vehicle if space permits.Technician B says modern compressors can be removed and reinstalled without discharging the rest of the system.Who is correct?

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

Question 22

What is the one moving part in a scroll compressor.

Question 23

A vehicle returns to the shop for a repeat failure of the compressor system due to compressor clutch slippage and overheating.Which of the following is the most likely cause?

A) A loose drive belt
B) High resistence in the comprssor clutch electrical circuit.
C) A low refrigerant charge level.
D) A faulty compressor clutch diode.

Question 24

A technician finds an air conditioning clutch will not engage.Upon initial testing the compressor is receiving both proper power and ground at the compressor clutch electrical connector,in addition the compressor input shaft turns freely by hand.Which of the following is the most likely cause?

A) Compressor clutch air gap too large.
B) A locked up compressor.
C) Low refrigerant level.
D) A faulty pressure cycling switch.

Question 25

If the compressor oil has been drained and it shows signs of metallic particles,all of the following should be done,EXCEPT:

A) The entire system should be flushed.
B) The receiver-drier or accumulator should be replaced after flushing.
C) All system inlet screens should be cleaned after flushing.
D) A full charge of heavier refrigeration oil should be added after flushing.

Question 26

How are all air conditioning compressor clutches applied and released?

Question 27

During the compression stroke in a single cylinder of a reciprocating piston compressor,which valve is held closed?

A) intake
B) exhaust
C) both
D) neither

Question 28

Low voltage at the compressor clutch coil could cause

A) no clutch application.
B)
B) a slipping clutch.
C) the clutch to stay engaged.
D) a and

Question 29

Why is it very important that the proper amount of oil be added after any service to a compressor?

Question 30

Replacement compressors are being discussed.Technician A says after installing a replacement compressor the receiver drier/accumulator should also be replced.Technician B says the replacement compressor is supplied with oil,and checking the level is not necessary.Who is correct?

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

Question 31

Technician A says a replacement compressor should have the same type of clutch and pulley as the old compressor.Technician B says the mounting brackets and other fasteners on a replacement compressor should be identical to those on the old compressor.Who is correct?

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

Question 32

To measure and adjust compressor clutch air gap,a ____ feeler gauge should be used.

A) carbon steel
B) soft steel
C) nonmetallic
D) none of the above

Question 33

During an A/C performance test at 1,500 rpm the compressor will not engage when the A/C switch is moved to the ON position.But if a jumper wire is connected to battery voltage and the compressor connector the clutch engages and operates normally.Technician A says that the A/C switch circuit fuse should be checked.Technician B says that the blower motor relay should be checked.Who is correct?

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

Question 34

Technician A says low pressure exists in an operating air conditioning system from the metering device outlet to the compressor inlet.Technician B says that high pressure exists in an operating air conditioning system from the compressor outlet to the metering device inlet.Who is correct?

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

Question 35

The A/C compressor clutch will not engage but the technician finds normal battery voltage at the compressor clutch connector.Which of the following is the most likely cause?

A) A faulty A/C control switch.
B) Low oil level in the A/C compressor.
C) Too great a compressor clutch air gap.
D) A compressor clutch relay stuck in the closed position.

Question 36

Explain the concept of reciprocating pistons as used in automotive air conditioning compressors.

Question 37

Technician A says when the compressor oil is drained,the oil can be reused if it looks good.Technician B says the type of new oil installed or added is not important as long as the compressor has enough oil.Who is correct?

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

Question 38

Why is it important that the compressor seals not be touched with the fingers?

Question 39

What must compressors be identified by?

Question 40

Why have many older compressor designs been discontinued even though they worked well?

Question 41

What can be determined by trying to rotate the drive plate by hand with the clutch disengaged?

Question 42

Explain the operation of an electronic variable displacement compressor.

Question 43

What is the compressor clutch?

Question 44

Explain the difference in operation between the reciprocating compressor crankshaft and the automobile engine crankshaft.

Question 45

Whatl is used in a high-voltage air conditioning compressor to keep voltage from conducting from the electric drive motor to the compressor case.

Question 46

What type of refrigerant compressor designs are used on Hybrid Electric vehicles?

Question 47

What are the two functions of the compressor in an automotive air conditioning system?

Question 48

Explain what happens in a single cylinder of a reciprocating piston compressor during the intake stroke.

Question 49

Electric motor driven air conditioning compressors used on Hybrid vehicles enable air conditioning operation even when what is not running?

Question 50

What are the two basic methods of temperature control for automotive air conditioning systems?