ASE A1 Engine Repair Practice Test

11. An engine is leaking oil past several oil seals. Technician A says a stuck closed PCV valve would cause these leaks. Technician B says a clogged crankcase breather tube would result in this condition. Who is correct?

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

11.

Answer A is wrong. A stuck closed PCV valve results in excessive crankcase pressure and oil forced past seals and gaskets.

Answer B is wrong. Engine breather hoses and filters get kinked or clogged, restricting flow and allowing blowby gases to build in the crankcase.

Answer C is correct. Both technicians are correct.

Answer D is wrong. Both technicians are correct.

12. Technician A says a rich air-fuel ratio can cause excessive carbon buildup on the engine's valves and pistons. Technician B says coolant entering the combustion chamber from a faulty head gasket produces excessive carbon buildup on the piston crown. Who is correct?

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

12.

Answer A is correct. Poor fuel and rich air-fuel ratios result in excessive carbon buildup on the valves and piston crowns.

Answer B is wrong. Coolant entering the combustion chamber from a blown head gasket will vaporize, soften, and then "wash" the carbon off the piston crown.

Answer C is wrong. Technician A is correct

Answer D is wrong. Technician A is correct

13. Technician A says piston pin offset locates the piston pin slightly closer to the thrust side of the engine. Technician B says piston side thrust mainly occurs during the power stroke. Who is correct?

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

13.

Answer A is wrong. Piston pin offset pushes the major thrust side tighter against the engine, affecting the connecting rod's angle, reducing piston slap, and providing efficient, quieter engine performance.

Answer B is wrong. During the power stroke, the force of combustion on the piston's dome and the connecting rod angle force the piston's thrust side against the cylinder wall.

Answer C is correct. Both Technicians are correct.

Answer D is wrong. Both Technicians are correct.

14. The skirt on one of an engine's pistons has excessive wear. Which of the following could be the cause?

  • A. Worn piston rings.
  • B. A clogged PCV valve.
  • C. A bent connecting rod.
  • D. Worn crankshaft bearings.

14.

Answer A is wrong. Worn piston rings result in oil consumption, blowby, and blue-gray exhaust.

Answer B is wrong. A clogged PCV valve results in high crankcase pressure and oil seeping past oil seals.

Answer C is correct. A bent connecting rod affects the piston's travel. The piston skirt on the piston's thrust side will have one-sided diagonal wear. A slightly bent connecting rod may not be noticeable during the initial inspection.

Answer D is wrong. Worn crankshaft main bearings result in a knocking or rapping noise and low oil pressure.

15. Technician A says VVT variable valve timing controls valve timing independent of crankshaft rotation. Technician B says thick contaminated oil will affect the operation of a VVT engine. Who is correct?

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

15.

Answer A is wrong. Today's engines have tight tolerances and typically use a different, lighter oil viscosity than older engines.

Answer B is wrong. Unchanged and contaminated oil causes problems with VVT systems. It clogs the camshaft's oil control valve, screen, and passages, resulting in fault codes and system failure.

Answer C is correct. Both technicians are correct.

Answer D is wrong. Both technicians are correct.