A-1 Engine Repair Q & A

1. A vacuum gauge is connected to the intake manifold of an engine. The needle fluctuates between (15 in. and 20 in. Hg) at idle. This reading indicates:
A. A normal condition.
B. Late ignition or valve timing.
C. A sticking valve or misfire.
D. A restricted exhaust system.
Answer C is correct. If the gauge readings fluctuate between (15 and 20 in Hg) this indicates a stuck valve or engine miss.
 
 
2. One of a cylinder heads valve tips is much higher than the others. The most likely cause of this is:
A. Weak spring tension.
B. Valve spring installed height.
C. Valve face.
D. Loose head bolts.
Answer C is correct. A worn valve face or valve seat is most likely the cause. Check the valve stem installed height whenever any of the valves have been replaced.
 
 
3. Two technicians are discussing a ballooned oil filter. What is the most likely cause of this condition:
A. Stuck open oil pressure relief valve.
B. Stuck closed oil pressure relief valve.
C. Stuck open oil filter bypass valve.
D. Contaminated oil.
Answer B is correct. A stuck closed oil pressure relief valve could cause high oil pressure and a ballooned oil filter.
 
 
4. Technician A says that torque to yield bolts can always be reused. Technician B says that torque to yield bolts can be reused as long as they are cleaned and oiled before they are re-installed and torqued. Who is correct?
A. Technician A
B. Technician B
C. Both A and B
D. Neither Technician A or B
Answer D is correct. Neither technician is correct
 
 
5. The best tool for checking crankshaft end-play is a:
A. Bore gauge
B. Digital micrometer
C. Dial indicator
D.None of the above
Answer C is correct. A dial gauge is used to measure end-play clearance
 
 
6. A vehicles cooling system is loosing coolant. There is major corrosion around the aluminum water pump. Which of these are the most likely cause.
A. Stuck open thermostat.
B. Electrolysis.
C. Loose radiator cap.
D. Faulty head gasket.
Answer B is correct. Electrolysis causes corrosion of dissimilar metals in a cooling system. The weaker metal of the two (aluminum) will corrode. It’s amazing, if you haven’t heard of it read the “Learn more about guy…”
 
 
7. A technician installs a radiator pressure tester on the radiator of a cold engine. After starting the engine the pressure quickly rises to 18 psi. Technician A says this is a normal condition. Technician B says the engine may have a leaking cylinder head gasket. Who is correct?
A. Technician A
B. Technician B
C. Both A and B
D. Neither Technician A or B
Answer B is correct. A leaking head gasket will force combustion into the coolant system causing an increase in system pressure.
 
 
8. Two Technicians are discussing the PCV system on an engine. Technician A says a stuck closed PCV valve could cause engine oil seals to leak. Technician B says that the PCV system functions to allow the blow-by gases from the crankcase to flow into the intake manifold for re-combustion. Who is correct?
A. Technician A
B. Technician B
C. Both A and B
D. Neither Technician A or B
Answer C is correct. A correct PCV valve will cause pressure to build in the crankcase forcing oil past engine seals. The PCV system is a one-way system that allows blow-by gases from the crankcase to flow into the intake manifold for re combustion.
 
 
9. An OHC engine has recently had the cylinder head replaced. The engine runs rough and stumbles. Technician A says this may be caused by the valve timing. Technician B says it is more likely the head gasket bolts do not have enough torque. Who is correct?
A. Technician A
B. Technician B
C. Both A and B
D. Neither Technician A or B
Answer A is correct. It is common to adjust the valves when tuning or after replacing the cylinder head. Also inspect cylinder valve overlap, lift, and duration.
 
 
10. A vehicle has heavy white smoke emitting from its tailpipe at all engine speeds. The cause of this problem is:
A. Worn Piston Rings.
B. A Leaking Head Gasket
C. Worn Valve Seals
D. A Leaking Fuel Injector
Answer B is correct. A leaking head gasket would cause coolant to leak from the jacket to the cylinder producing white/gray smoke.
 
 
11. Technician A says a worn valve spring may float at high RPM’s. Technicain B says valve float will result in a worn valve seat. Who is correct?
A. Technician A
B. Technician B
C. Both Technician A and B
D. Neither Technician A or B
Answer C is correct. Both technicians are correct
 
 
12. A vehicle briefly blows bluish/gray smoke from the tailpipe only when first started in the mourning. The most likely cause of this condition is:
A. Worn Piston Rings
B. Lean Fuel Condition
C. Leaking Fuel Injector
D. Leaking Valve Seal
Answer D is correct. A leaking valve seal will cause oil to leak into the cylinders chamber over time, usually overnight.
 
 
13. Technician A says an engines main bearing insert has a hole that must align with the matching bores oil supply hole. Technician B says that crankshaft bore alignment can be checked with a feeler gauge and a straightedge. Who is correct?
A. Technician A
B. Technician B
C. Both Technician A and B
D. Neither Technician A or B
Answer C is correct. Always make sure the two holes and all bores are in alignment when replacing the crankshaft bearing inserts.
 
 
14. A cylinder power balance test is being performed on a vehicle with sequential fuel infection. Two adjacent cylinders are under performing. Technician A says this could be due to a faulty head gasket. Technician B says this could be due to leaking secondary insulation. Who is correct? Who is correct?
A. Technician A
B. Technician B
C. Both Technician A and B
D. Neither Technician A or B
Answer C is correct. Both restricted fuel injectors and leaking secondary wires will reduce the cylinders contribution. It could also be a faulty or blown head gasket.
 
 
15. Two technicians are discussing hydraulic lifter preload. Technician A says excessive preload will cause high manifold vacuum. Technician B says insufficient preload will cause excessive valve train noise. Who is correct?
A. Technician A
B. Technician B
C. Both Technician A and B
D. Neither Technician A or B
Answer B is correct. Insufficient lifter preloads will cause valve train noise.
 
 
16. Technician A says the valves in many interference engines open further into the combustion chamber that than those of a non-interference engine. Technician B says if the timing belt were to break in an interference engine due to a seized bearing or water pump, damage to the valves or pistons may occur. Who is correct?
A. Technician A
B. Technician B
C. Both Technician A and B
D. Neither Technician A or B
Answer C is correct. The valve can strike the piston when out of timing in an interference engine.
 
 
17. Technician A says a flex fan will increase its pitch at higher engine speeds. Technician B says a viscous fan clutch contains a silicon based fluid and should be checked for leaks. Who is correct?
A. Technician A
B. Technician B
C. Both Technician A and B
D. Neither Technician A or B
Answer B is correct. A viscous fan clutch contains a silicon based fluid.
 
 
18. Two technicians are discussing the engine coolant temperature sensor. Technician A says this sensor will affect the torque converter clutch application. Technician B says this sensor will affect the engines fuel mixture. Who is correct?
A. Technician A
B. Technician B
C. Both Technician A and B
D. Neither Technician A or B
Answer C is correct. The ECT effects both TCC application and fuel mixture.
 
 
19. A spark plug is removed and compressed shop air is introduced to the #1 cylinder while at TDC. Bubbles are seen coming out of the radiator neck. The most likely cause is:
A. Bent Intake Valve
B. Worn Piston Rings
C. Burned Exhaust Valve
D. Leaking Head Gasket
Answer D is correct. Air is leaking from the cylinder, past the gasket, and into the coolant jacket.
 
 
20. A vehicle has a clogged catalytic converter. The least likely cause of this is.
A. Rich Fuel Condition
B. Leaking Fuel Injector
C. Cracked Intake Manifold
D. Fouled Spark Plug
Answer C is correct. This is a least likely type question. A rich not lean condition is most likely to cause internal damage to a catalytic converter.
 
 
21. Two technicians are performing a wet compression test on a four cylinder engine, one of the cylinders is low and stays the same after adding oil. Technician A says the engine needs piston rings. Technician B says the engine has a faulty valve. Who is correct?
A. Technician A
B. Technician B
C. Both Technician A and B
D. Neither Technician A or B
Answer B is correct. If there is no change in the compression reading after adding oil to the cylinder the cylinder has a faulty valve.
 
 
22. Technician A says the engines main caps should be replaced in the same order they are removed. Technician B says a worn thin thrust bearing will result in excessive crankshaft end-play. Who is correct?
A. Technician A
B. Technician B
C. Both Technician A and B
D. Neither Technician A or B
Answer C is correct. Both technicians are correct.
 
 
23. A compression test is being performed on a vehicle. The #1 cylinder is 30lbs. lower than the rest. The pressure increases after injecting oil into the cylinder. Technician A says that excessive carbon buildup is the cause of this condition. Technician B says this test indicates one of the cylinders valves may be defective. Who is correct?
A. Technician A
B. Technician B
C. Both Technician A and B
D. Neither Technician A or B
Answer D is correct. When injecting oil increases the cylinders pressure, the piston rings are faulty. Compression is blowing past this weak seal.
 
 
24. Technician A says the ridge must be removed before installing new pistons. Technician B says a ridge reamer is used. Who is correct?
A. Technician A
B. Technician B
C. Both Technician A and B
D. Neither Technician A or B
Answer C is correct. The ridge is removed with a ridge reamer before installing the new pistons.
 
 
25. During a cylinder leakage test air bubbles appear coming from the radiator neck. Technician A says this may be caused by a leaking intake valve. Technician B says the engine may have a crack in the engine block. Who is correct?
A. Technician A
B. Technician B
C. Both Technician A and B
D. Neither Technician A or B
Answer B is correct. The blocks deck area and cylinder head will allow compression to leak into the coolant jacket.

This post was written by: Martin Hand

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Martin Hand

About Martin Hand

ASE Certified L1 Advanced Mastertech. Martin Hand has over 15 years experience in Asian and European Import Auto Repair. Specializing in electrical diagnosis, engine performance, AT/MT transmission repair/rebuild. Martin is also pursuing a degree in Computers Science & Information Systems starting at Portland Community College while he plans to transfer to OIT. Certified in Java application level programming, experienced with other languages such as PHP, Ruby, JavaScript and Swift. Martin has future plans of automotive diagnostic software development.