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SKM Motor Vehicle Mechanic L2 Practice Questions - SKM Motor Vehicle Mechanic Level 2 Exam
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Question
1
of 25
QUESTION 1 / 25
What is the primary function of the engine thermostat in a vehicle's cooling system?
Choose one answer below.
A
To measure the oil pressure inside the engine block
✓
B
To regulate the coolant temperature by controlling flow to the radiator
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C
To speed up the flow of coolant through the water pump
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D
To mix coolant and distilled water in a 50:50 ratio
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QUESTION 2 / 25
Which tool should a mechanic use to inspect and adjust the gap of a spark plug?
Choose one answer below.
A
Dial indicator
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B
Vernier caliper
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C
Wire feeler gauge or spark plug gap tool
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D
Outside micrometer
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QUESTION 3 / 25
In the engine oil viscosity rating '10W-40', what does the '10W' indicate?
Choose one answer below.
A
The oil's flow characteristics at low temperatures (winter)
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B
The oil's maximum operating temperature of 10 degrees Celsius
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C
The oil's weight in kilograms per liter
✓
D
The oil change interval of 10,000 kilometers
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QUESTION 4 / 25
What is the primary function of the Positive Crankcase Ventilation (PCV) valve?
Choose one answer below.
A
To increase fuel pressure to the injectors
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B
To filter out dust from entering the intake manifold
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C
To route blow-by gases from the crankcase back into the combustion chambers
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D
To spray oil onto the cylinder walls to lubricate the pistons
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QUESTION 5 / 25
What does a continuous blue-grey smoke from the vehicle's exhaust pipe typically indicate?
Choose one answer below.
A
Unburned fuel escaping from a rich air-fuel mixture
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B
Coolant leaking into the combustion chamber
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C
Engine oil burning in the combustion chamber
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D
Condensation in the exhaust system during cold mornings
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QUESTION 6 / 25
Which of the following is the most appropriate service interval practice for the engine oil filter?
Choose one answer below.
A
Clean and blow with compressed air every 5,000 km
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B
Replace it every time the engine oil is changed
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C
Replace it every third engine oil change
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D
Wash it with petrol and reinstall it
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QUESTION 7 / 25
What is the function of the pressure valve inside a radiator cap?
Choose one answer below.
A
To prevent the coolant from flowing into the water pump
✓
B
To increase the pressure inside the cooling system, raising the boiling point of the coolant
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C
To spray coolant into the cylinder head when it gets hot
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D
To keep air trapped inside the radiator at all times
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QUESTION 8 / 25
What is the primary consequence of operating a vehicle with a severely clogged engine air filter?
Choose one answer below.
A
Excessive coolant loss and engine overheating
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B
Increased fuel consumption and reduced engine power output
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C
Engine oil leaking from the valve cover gasket
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D
An increase in engine idle speed (RPM)
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QUESTION 9 / 25
Which of the following steps must be completed before performing a cylinder compression test on a petrol engine?
Choose one answer below.
A
Keep the engine running at idle throughout the test
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B
Disconnect the battery negative terminal to keep starter motor active
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C
Disable the ignition system and disable the fuel injection system
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D
Fully close the throttle plate to block air intake
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QUESTION 10 / 25
A mechanic performs a dry compression test and finds low compression in cylinder 3. After squirting a small amount of engine oil into the cylinder (wet test), the compression reading increases significantly. What does this indicate?
Choose one answer below.
A
The intake or exhaust valves are leaking
✓
B
The piston rings or cylinder walls are worn
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C
The cylinder head gasket is blown between cylinders 2 and 3
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D
The cylinder head is cracked
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QUESTION 11 / 25
What is the likely effect on engine operation if the spark plug gap is set significantly smaller than the manufacturer's specification?
Choose one answer below.
A
The ignition coil will overheat and melt instantly
✓
B
The engine will experience a weak spark, potentially causing misfires under load or at high idle
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C
The spark plug electrodes will melt and fuse together
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D
The engine timing will automatically advance by 10 degrees
✓
QUESTION 12 / 25
Which symptom would most likely occur if the engine thermostat is stuck in the open position?
Choose one answer below.
A
The engine will overheat within 5 minutes of driving
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B
The coolant level in the expansion tank will drop rapidly
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C
The engine will take an unusually long time to reach normal operating temperature
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D
The electric radiator cooling fan will run continuously
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QUESTION 13 / 25
A vehicle overheats only when idling or driving slowly in traffic, but the engine temperature returns to normal when driving on the highway. What is the most likely cause?
Choose one answer below.
A
The radiator core is completely blocked with debris
✓
B
The water pump impeller is completely broken off
✓
C
The electric cooling fan or its temperature switch is faulty
✓
D
The thermostat is stuck in the closed position
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QUESTION 14 / 25
During a routine inspection, a mechanic notices that the engine oil on the dipstick looks like a milky-brown, frothy mixture. What does this suggest?
Choose one answer below.
A
The engine oil is long overdue for an oil change
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B
Coolant has leaked into the engine oil supply
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C
The engine is burning fuel with high sulfur content
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D
Power steering fluid has been mistakenly added to the engine
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QUESTION 15 / 25
What is the most likely consequence of adjusting an engine's timing belt with excessive tension?
Choose one answer below.
A
The engine valves will stay open longer than normal
✓
B
Premature wear of the water pump bearing, idler pulley, and belt teeth
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C
The engine will run with an advanced ignition timing
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D
The belt will stretch and slip, reversing the engine rotation
✓
QUESTION 16 / 25
What is a common cause of engine spark knock (detonation or pinging)?
Choose one answer below.
A
Excessive carbon build-up in the combustion chambers creating hot spots
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B
Using a fuel with a higher octane rating than recommended
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C
An extremely rich air-fuel mixture
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D
Ignition timing that is retarded too far
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QUESTION 17 / 25
Why is it necessary to have a specified clearance (lash) between the valve stem and the rocker arm on mechanical valve trains?
Choose one answer below.
A
To allow oil to flow into the combustion chamber
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B
To ensure the valves can close completely when they expand due to engine heat
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C
To increase the speed at which the valves open
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D
To prevent the valve springs from compressing too far
✓
QUESTION 18 / 25
A vehicle emits blue-grey smoke from the tailpipe only for a few seconds immediately after engine startup, but the exhaust runs clean once driving. What is the most likely cause?
Choose one answer below.
A
Worn piston rings
✓
B
A leaking intake manifold gasket
✓
C
Worn valve stem seals
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D
A cracked exhaust manifold
✓
QUESTION 19 / 25
What is the purpose of using a dual-pass radiator instead of a single-pass radiator in high-performance cooling applications?
Choose one answer below.
A
To separate the oil cooling function from the coolant function
✓
B
To force the coolant to travel across the radiator twice, increasing heat dissipation
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C
To allow the use of two different types of coolant simultaneously
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D
To increase the pressure of the coolant without using a water pump
✓
QUESTION 20 / 25
What is the correct procedure for tightening cylinder head bolts during engine reassembly?
Choose one answer below.
A
Tighten them clockwise starting from the front left bolt and moving in a circle
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B
Tighten them in a spiral sequence starting from the center bolts outward, in multiple torque stages
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C
Tighten each bolt to its maximum torque rating in a single stage, starting from the outside corners
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D
Use an impact wrench to tighten all bolts until they stop turning
✓
QUESTION 21 / 25
During an engine cylinder leakage (leak-down) test, air bubbles are seen rising in the radiator neck. What does this diagnosis indicate?
Choose one answer below.
A
Leaking exhaust valves
✓
B
Leaking intake valves
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C
A blown head gasket or cracked cylinder head/block
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D
Worn piston rings letting air slip into the crankcase
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QUESTION 22 / 25
When performing a cylinder leak-down test, air can be heard escaping through the dipstick tube and oil filler cap. What is the cause?
Choose one answer below.
A
Worn valve guides in the cylinder head
✓
B
A cracked intake manifold runner
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C
Worn piston rings or cylinder wall damage
✓
D
A leaking head gasket near the timing cover
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QUESTION 23 / 25
What is the consequence of adjusting valve clearance (lash) to be wider than the manufacturer's specification?
Choose one answer below.
A
The valves will open too early and stay open too long
✓
B
Reduced valve lift and duration, accompanied by excessive mechanical noise (clatter)
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C
The valves will remain slightly open when hot, causing misfires
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D
The valve springs will bind and break
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QUESTION 24 / 25
An interference-design engine skips two teeth on its timing belt while running. What is the most critical risk?
Choose one answer below.
A
The alternator will stop generating voltage
✓
B
Physical contact between the pistons and open valves, causing catastrophic engine damage
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C
The oil pump will lose prime and cause low oil pressure
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D
The engine will run backwards, blowing exhaust out of the intake
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QUESTION 25 / 25
What is the primary cause of high pressure build-up inside the engine crankcase?
Choose one answer below.
A
A stuck-open cooling thermostat
✓
B
Excessive clearance in the oil pump gears
✓
C
Severe blow-by past worn piston rings combined with a clogged PCV valve
✓
D
A restricted exhaust catalytic converter
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