ASE A7 Heating Air Conditioning Practice Test

31. During a visual inspection, an oily spot is found on a hose leading from the compressor. Technician A says there may be a refrigerant leak in the system. Technician B says to add mineral oil to lubricate an R134a refrigerant system. Who is correct?

  • A. Technician A
  • B. Technician B
  • C. Both A and B
  • D. Neither A or B

31.

Answer A is correct. Finding an oily spot on an A/C hose is a quick and easy way to spot a refrigerant leak. Closer inspection and testing will be necessary.

Answer B is wrong. R134a air conditioning systems require PAG oil. Mineral oil is compatible with R12 refrigerant.

Answer C is wrong. Technician A is correct.

Answer D is wrong. Technician A is correct.

Snapshot of a scan tool display.

32. The inputs of a 134a refrigerant system in a passenger car are scanned. The display is shown above. Which of the following is correct?

  • A. The system has been overcharged with refrigerant.
  • B. The system has an undercharge.
  • C. The outside air temperature is preventing compressor clutch operation.
  • D. None of these statements are correct.

32.

Answer A is wrong. The system scan shown has an acceptable charge.

Answer B is wrong. The charge is sufficient.

Answer C is wrong. Most systems prevent compressor clutch operation when the temperature is in the thirties.

Answer D is correct. None of these are correct.

33. A refrigerant service station is used to recover, evacuate, and recharge an air conditioning system. Technician A says the needle on the gauge should not increase and should remain steady after the recovery process is complete. Technician B says the system should be inspected for leaks if the needle moves more than .01 "hg after the evacuation process is complete. Who is correct?

  • A. Technician A
  • B. Technician B
  • C. Both A and B
  • D. Neither A or B

33.

Answer A is wrong. The needle should remain steady after recovery. If there’s an increase in pressure, there’s refrigerant left in the system.

Answer B is wrong. After the evacuation process, the system can rest for a specified time. If the needle moves, inspect the system for leaks.

Answer C is correct. Both Technicians are correct.

Answer D is wrong. Both Technicians are correct.

34. A vehicle has poor air conditioning performance. The customer has added R134a refrigerant to the system. Technician A says to use a refrigerant identifier. Technician B says refrigerant mixtures do not affect system pressures. Who is correct?

  • A. Technician A
  • B. Technician B
  • C. Both A and B
  • D. Neither A or B

34.

Answer A is correct. Use a refrigerant identifier to identify R12, R134a, 1234yf refrigerant, hydrocarbons, and air.

Answer B is wrong. These refrigerants should not be mixed because they are different compounds with different characteristics. The average shop recycling machine cannot separate R12, R134a, and 1234yf refrigerants.

Answer C is wrong. Technician A is correct.

Answer D is wrong. Technician A is correct.

35. A squeal is heard when the compressor clutch first engages. The MOST likely cause of this condition is:

  • A. A stretched accessory belt.
  • B. A low refrigerant charge.
  • C. A faulty clutch pulley bearing.
  • D. A faulty clutch relay.

35.

Answer A is correct. A stretched accessory belt will cause a squeal when the clutch first engages.

Answer B is wrong. A low refrigerant charge results in no A/C or a rapid cycling compressor clutch.

Answer C is wrong. A faulty pulley bearing would make a growling or squealing sound whenever the engine runs.

Answer D is wrong. A faulty clutch relay typically results in an inoperative compressor clutch.