ASE A1 Engine Repair Practice Test

46. The engine overheats after replacing the lower radiator hose and adding coolant. Which of the following is MOST likely causing this condition?

  • A. A faulty water pump impeller.
  • B. A leaking head gasket.
  • C. A faulty fan motor relay.
  • D. An air pocket in the cooling system.

46.

Answer A is wrong. After draining an engine's coolant, stubborn air pockets can form in the cooling system.

Answer B is wrong. A leaking head gasket produces tiny air bubbles in the radiator neck, overheating, and white-colored exhaust.

Answer C is wrong. A faulty fan motor relay is not the MOST likely answer.

Answer D is correct. Air pockets form after draining the engine's coolant. Some vehicles are more prone to this problem than others.

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47. A vehicle is emitting black-colored exhaust. Which of these could be the cause?

  • A. Oil is burning in the combustion chamber.
  • B. Coolant is burning in the combustion chamber.
  • C. A rich air-fuel ratio.
  • D. A lean air-fuel ratio.

47.

Answer A is wrong. Oil burning in the combustion chamber results in blue-gray exhaust.

Answer B is wrong. Coolant entering the combustion chamber results in white-colored exhaust.

Answer C is correct. A rich air-fuel ratio causes black-colored exhaust.

Answer D is wrong. A rich air-fuel ratio produces high HC emissions and black sooty deposits around the tailpipe.

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48. All of the following statements are true about an engine's PCV system EXCEPT:

  • A. A stuck closed PCV valve results in excessive crankcase pressure.
  • B. A stuck open PCV valve results in a rough idle.
  • C. Oil leakage indicates a problem with the system.
  • D. The PCV valve should not rattle when shaken.

48.

Answer A is wrong. A stuck closed PCV valve causes excessive crankcase pressure.

Answer B is wrong. A stuck open PCV valve or leaking hose results in a rough idle and drivability issues.

Answer C is wrong. Oil leakage indicates a problem with the system.

Answer D is correct. The PCV valve should rattle when shaken.

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49. A cylinder power balance test indicates two adjacent cylinders are underperforming. Which of the following is causing this test result?

  • A. A faulty fuel injector.
  • B. A bad exhaust valve.
  • C. Worn piston rings.
  • D. A leaking head gasket.

49.

Answer A is wrong. A faulty fuel injector will only affect the cylinder it services.

Answer B is wrong. A faulty exhaust valve will affect only one cylinder.

Answer C is wrong. Worn piston rings affect all of the engine's cylinders.

Answer D is correct. Perform a cylinder power balance test to compare each cylinder's effectiveness and find a weak or problem cylinder(s). For example, a leaking or blown head gasket can leak compression between two adjacent cylinders.

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50. Technician A says insufficient hydraulic lifter preload results in excessive valve train noise. Technician B says excessive hydraulic lifter preload produces a high intake manifold vacuum. Who is correct?

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

50.

Answer A is correct. Insufficient lifter preload will cause valve train noise.

Answer B is wrong. Excessive hydraulic lifter preload causes a low intake manifold vacuum.

Answer C is wrong. With a hydraulic lifter, first set the gap to zero lash and then set the preload.

Answer D is wrong. This initial zero lash adjustment prevents valve tap and is why hydraulic lifters have a quieter operation.

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