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 that a rich air-fuel ratio can result in excessive carbon buildup on the engine's valves and pistons. Technician B says coolant entering the combustion chamber results in excessive carbon buildup in the cylinder and piston crowns. 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. The intake valves in gasoline direct injection engines do not benefit from fuel cleaning the intake port and valve.

Answer B is wrong. Coolant entering the combustion chamber will typically 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 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. Technician A says a bent connecting rod results in excessive piston skirt wear. Technician B says a bent connecting rod can result in low cylinder compression. Who is correct?

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

14.

Answer A is wrong. Typically a bent rod is caused by overrevving, detonation, or fluid entering the cylinder ending in a hydrolocked engine.

Answer B is wrong. A slightly bent connecting rod may not be noticeable during the initial inspection. However, it may appear as one-sided diagonal wear on the skirt located on the thrust side of the piston.

Answer C is correct. Both technicians are correct.

Answer D is wrong. Both technicians are correct.

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 contaminated oil causes problems with VVT systems. It clogs the control valve, screen, and passages in the camshaft resulting in system failure.

Answer C is correct. Both technicians are correct.

Answer D is wrong. Both technicians are correct.