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SVP Light Vehicle Mechanic study materials
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SVP Light Vehicle Mechanic practice questions

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Question 1Workshop Safety, Tools and Equipment

A technician is sharpening a chisel on a bench grinder. What is the minimum eye protection required for this task?

  1. Ordinary prescription spectacles
  2. A welding helmet with a dark filter lens
  3. A dust mask with ear plugs
  4. Safety glasses with side shields Correct answer.

Explanation

Grinding throws high-speed fragments of wheel and metal, so eye protection must be impact rated and closed at the sides. Safety glasses with side shields, or goggles, meet that minimum for bench work.

Question 2Workshop Safety, Tools and Equipment

A vehicle has been raised with a trolley jack so a technician can work underneath it. What must be done before work starts?

  1. Leave the jack holding the load
  2. Support it on stands rated for the load Correct answer.
  3. Lower the vehicle back onto its wheels first
  4. Place bricks under the sump

Explanation

A jack is a lifting device, not a supporting device, and can lose pressure without warning. The raised vehicle must rest on stands of adequate rated capacity placed at the proper support points before anyone goes under it.

Question 3Workshop Safety, Tools and Equipment

How should a click-type torque wrench be stored after use?

  1. Back at the lowest setting on its scale Correct answer.
  2. Hanging by the drive square from a hook
  3. At its maximum setting to relieve spring stress
  4. Oiled and left in its case at the set torque

Explanation

A click-type wrench works by compressing an internal spring, and leaving it compressed between jobs causes the spring to take a set and drift out of calibration. Winding it back to the lowest scale setting removes that load during storage.

Question 4Workshop Safety, Tools and Equipment

A small pool of petrol ignites in the workshop. Which extinguisher is suitable for this fire?

  1. Dry powder (Class D)
  2. Wet chemical (Class F)
  3. Water (Class A)
  4. Foam or CO2 (Class B) Correct answer.

Explanation

Petrol is a flammable liquid, which places it in Class B, and foam, CO2 and dry powder are all rated for that class. The extinguisher must also be matched to the surrounding hazards so the fire is not spread.

Question 5Workshop Safety, Tools and Equipment

Why must compressed air never be directed at a person's skin?

  1. Air can enter the skin and cause fatal injury Correct answer.
  2. It removes protective oils from the hands
  3. It can blow dust into the eyes only
  4. It makes the skin too cold to work safely

Explanation

Air delivered at workshop pressure can pass through a break in the skin and enter the bloodstream, causing air embolism and death. This is why air lines are never used for cleaning clothing or skin, regardless of pressure setting.

Question 6Workshop Safety, Tools and Equipment

A metric micrometer has 50 thimble divisions and each sleeve division equals 0.5 mm. The sleeve shows 7 divisions and the thimble reads 24. What is the measurement?

  1. 7.24 mm
  2. 3.86 mm
  3. 3.62 mm
  4. 3.74 mm Correct answer.

Explanation

Sleeve reading is 7 x 0.5 = 3.50 mm and the thimble contributes 24 x 0.01 = 0.24 mm. Adding them gives 3.74 mm.

Question 7Workshop Safety, Tools and Equipment

A technician wants to measure the resistance of a fuel injector with a digital multimeter. What is the correct preparation?

  1. Turn the ignition off and isolate the part Correct answer.
  2. Set the meter to the highest DC volts range
  3. Use the meter's current setting instead
  4. Back-probe with the engine running

Explanation

An ohmmeter supplies its own small test current, so any external voltage in the circuit gives a false reading and can damage the meter. The circuit must be dead and the component disconnected or isolated before resistance is measured.

Question 8Workshop Safety, Tools and Equipment

What is the maximum recommended gap between a bench grinder's tool rest and the wheel face?

  1. 5 mm
  2. 3 mm Correct answer.
  3. 10 mm
  4. 1 mm

Explanation

The tool rest is set close to the wheel, in the order of 3 mm or less, so that a workpiece cannot be drawn down into the gap between rest and wheel. The gap is checked and adjusted as the wheel wears down.

Question 9Workshop Safety, Tools and Equipment

A rusted hex bolt head is starting to round off. Which tool choice gives the best chance of removing it undamaged?

  1. An adjustable wrench tightened by hand
  2. A six-point socket of the exact nominal size Correct answer.
  3. A twelve-point socket for easier fit
  4. A socket one size larger with a shim

Explanation

A six-point socket grips all six flats of the head at once, spreading the load and reducing the chance of further rounding. Twelve-point and adjustable tools contact fewer flats and concentrate stress on the corners.

Question 10Workshop Safety, Tools and Equipment

Where must the lift pads of a two-post hoist be positioned under a vehicle?

  1. Under the suspension arms and lines
  2. Under the floor pan between the wheels
  3. Anywhere along the outer sill seam
  4. At the maker's marked lift points Correct answer.

Explanation

Manufacturers designate reinforced lift points that carry the vehicle's weight without deformation. Using any other area risks crushing panels, pipes or fuel and brake lines.

Question 11Workshop Safety, Tools and Equipment

Why must the area around a lead-acid battery be ventilated while it is on charge?

  1. To keep the electrolyte at the right level
  2. To stop the charger from overheating
  3. To stop acid vapour condensing on plates
  4. To disperse explosive hydrogen gas Correct answer.

Explanation

Charging produces hydrogen, which forms an explosive mixture with air at quite low concentrations. Ventilation keeps the gas below that level and removes any ignition risk from sparks or hot surfaces.

Question 12Workshop Safety, Tools and Equipment

Why should an impact wrench be used only with impact-rated sockets?

  1. Impact sockets have thinner walls for access
  2. Chrome sockets grip the fastener more tightly
  3. Impact sockets are only for use by hand
  4. Chrome sockets may shatter under shock Correct answer.

Explanation

Impact sockets are made from a softer, tougher steel that absorbs repeated shock loads without cracking. Chrome hand sockets are harder and can fracture and throw fragments when driven by an impact tool.

Question 13Workshop Safety, Tools and Equipment

A straight extension bar is added between a torque wrench and a socket. How does this affect the torque delivered to the fastener?

  1. It doubles when the extension is long
  2. It stays the same along the same axis Correct answer.
  3. It increases in proportion to the extension
  4. It reduces because of the extra length

Explanation

Torque equals force multiplied by the perpendicular distance from the pivot, so a straight extension in line with the wrench handle leaves that distance unchanged. Only an offset such as a crowfoot alters the effective lever length.

Question 14Workshop Safety, Tools and Equipment

A torque wrench with an effective length of 400 mm is fitted with a crowfoot that extends the lever arm by 60 mm in line with the handle. The specification is 100 Nm at the fastener. What wrench setting is required?

  1. 115 Nm
  2. 94 Nm
  3. 100 Nm
  4. 87 Nm Correct answer.

Explanation

With an in-line extension the setting is reduced in the ratio of the original length to the new length: 100 x 400 / 460 = 87 Nm. Leaving the wrench at 100 Nm would overtorque the fastener by about 15 percent.

Question 15Workshop Safety, Tools and Equipment

A cylinder head bolt is specified as torque-to-yield. How is it installed?

  1. Torque only with a beam-type wrench
  2. Torque to spec, then reuse up to three times
  3. Torque to a figure then turn a set angle Correct answer.
  4. Torque to a lower figure and check stretch

Explanation

Torque-to-yield bolts are tightened past their elastic limit, so the specified torque is followed by an angular turn that stretches the bolt a controlled amount. Because they are permanently deformed, they are replaced rather than reused.

Question 16Workshop Safety, Tools and Equipment

A technician finds an unlabelled bottle of clear solvent left on a bench. What is the correct action?

  1. Use it up quickly on rags outdoors
  2. Smell it to identify the contents
  3. Dispose of it as unknown hazardous waste Correct answer.
  4. Label it 'solvent' and put it on the shelf

Explanation

A container without identification cannot be safely stored, used or combined with other wastes, so it is treated as unknown hazardous waste and passed to a licensed disposal route. Identification by smell or guesswork exposes the technician to unknown hazards.

Question 17Engine Mechanical Systems

In a four-stroke spark-ignition engine, what is the correct sequence of strokes?

  1. Power, intake, compression, exhaust
  2. Compression, intake, power, exhaust
  3. Intake, power, compression, exhaust
  4. Intake, compression, power, exhaust Correct answer.

Explanation

The four-stroke cycle always runs intake, compression, power, then exhaust, with the crankshaft making two revolutions per complete cycle. The power stroke must follow compression because the compressed charge is what burns.

Question 18Engine Mechanical Systems

What is the main job of the oil control ring on a piston?

  1. Scrapes excess oil from the bore back to the sump Correct answer.
  2. Holds the gudgeon pin in the piston boss
  3. Locks the piston to the connecting rod
  4. Seals combustion pressure against the bore

Explanation

The oil control ring sits below the compression rings and its scraping edges meter the oil film, returning surplus oil to the sump. Controlling the film prevents oil from passing the rings and burning in the chamber.

Question 19Engine Mechanical Systems

What is the function of the valve spring in a poppet valve train?

  1. Seals the valve stem against oil loss
  2. Locks the valve into its guide
  3. Opens the valve against camshaft pressure
  4. Closes the valve and keeps the follower on the cam Correct answer.

Explanation

The camshaft only pushes a valve open; the spring supplies the force that closes it and keeps the follower in contact with the lobe throughout the cycle. Losing contact would cause valve float and noise at high speed.

Question 20Engine Mechanical Systems

What is the primary function of a cylinder head gasket?

  1. Seals combustion gas, coolant and oil between head and block Correct answer.
  2. Keeps the head aligned with the block dowels
  3. Stops oil from reaching the camshaft bearings
  4. Carries combustion heat into the coolant jacket

Explanation

The head gasket is the pressure boundary between the block and head, sealing combustion chambers as well as the coolant and oil transfer passages that cross the joint face. A failure at any of these boundaries shows up as compression loss, coolant loss or oil mixing.

Question 21Engine Mechanical Systems

What does the timing belt on an engine do?

  1. Keeps the camshaft rotating in step with the crankshaft Correct answer.
  2. Balances the crankshaft at high speed
  3. Drives the alternator and water pump
  4. Sets the ignition firing order

Explanation

A timing belt or chain links the crankshaft sprocket to the camshaft sprocket at a fixed 2:1 ratio so the valves open at the correct point in each piston stroke. If this relationship is lost, valve timing and engine operation are affected.

Question 22Engine Mechanical Systems

Which component converts the piston's reciprocating motion into rotation?

  1. The flywheel
  2. The camshaft
  3. The gudgeon pin
  4. The crankshaft Correct answer.

Explanation

The connecting rod transfers force from the piston to the crank throw, and the offset of that throw turns linear force into torque about the crankshaft axis. The crankshaft therefore delivers the engine's rotary output.

Question 23Engine Mechanical Systems

Why is engine oil delivered under pressure to the bearings?

  1. To raise the octane rating of the fuel
  2. To increase compression pressure in the cylinders
  3. To cool the exhaust valves directly
  4. To maintain a lubricating film between moving surfaces Correct answer.

Explanation

A pressurised oil film separates the journal from the bearing shell so the surfaces do not touch at operating speed. Once the film is lost, metal-to-metal contact rapidly destroys the bearing.

Question 24Engine Mechanical Systems

What is the function of the thermostat in the cooling system?

  1. Pumps coolant around the engine
  2. Switches the radiator fan on and off
  3. Vents pressure when the system overheats
  4. Regulates coolant flow to hold operating temperature Correct answer.

Explanation

The thermostat is a wax-operated valve that stays closed while the engine is cold and opens as coolant temperature rises, allowing flow through the radiator. This keeps the engine within its designed operating band.

Question 25Engine Mechanical Systems

What is the likely result of setting exhaust valve clearance too tight on a mechanical valve train?

  1. The valve may not seat fully and can burn Correct answer.
  2. Valve train noise increases noticeably
  3. Valve spring pressure rises above specification
  4. The valve opens later than the cam specifies

Explanation

Clearance is there to guarantee the valve can close fully when the metal expands hot. Too little clearance holds the valve off its seat, so combustion gas leaks past and overheats the valve head.

Question 26Engine Mechanical Systems

Why must torque-to-yield cylinder head bolts be replaced rather than reused?

  1. Their threads are cut in the opposite direction
  2. They stretch permanently past their elastic limit when torqued Correct answer.
  3. They shrink when the engine cools down
  4. They lose a protective coating during removal

Explanation

Torque-to-yield bolts are tightened by angle past the yield point, giving a consistent clamp load but permanently stretching the shank. A reused bolt has already been stretched and will not hold the specified clamping force.

Question 27Engine Mechanical Systems

Which tool is used to check a bare cylinder head deck for warpage?

  1. A precision straight edge and feeler gauge Correct answer.
  2. A dial bore gauge
  3. A micrometer and telescoping gauge
  4. A vernier caliper

Explanation

Warpage is measured by laying a precision straight edge across the deck in several directions and trying feeler gauges at the gaps. The largest gap is compared with the manufacturer's flatness limit.

Question 28Engine Mechanical Systems

A dry compression test reads low on one cylinder, but the reading rises noticeably when a little oil is added. What does this indicate?

  1. A leaking intake valve
  2. A worn camshaft lobe
  3. Worn piston rings or a worn cylinder bore Correct answer.
  4. A blown head gasket

Explanation

Oil temporarily seals the gap between rings and bore, so a pressure rise on the wet test points to the rings or bore as the leak path. Valve or head gasket leaks are not sealed by adding oil.

Question 29Engine Mechanical Systems

A timing belt jumps two teeth on its sprockets. Which symptom is most likely?

  1. A steady fast idle with no misfire
  2. The starter motor fails to crank the engine
  3. Complete loss of oil pressure
  4. Rough running and misfire from incorrect valve timing Correct answer.

Explanation

The belt sets the fixed relationship between crank and cam, so skipping teeth retards or advances the whole valve event. The result is poor breathing, rough running and misfire, and on an interference engine possible valve damage.

Question 30Engine Mechanical Systems

A camshaft with one worn intake lobe will most directly cause what on the affected cylinder?

  1. Higher than normal compression
  2. Increased oil pressure at the gauge
  3. Reduced valve lift and poor cylinder filling Correct answer.
  4. A louder exhaust note at idle only

Explanation

The lobe profile controls how far and how long the valve opens. A worn lobe reduces lift and duration, so that cylinder draws in less air and produces less power.

Question 31Engine Mechanical Systems

What are the typical signs of worn main bearings?

  1. Blue smoke from the tailpipe at idle
  2. A chirping noise from the accessory belt
  3. Low oil pressure and a deep knocking sound Correct answer.
  4. Coolant loss with white exhaust smoke

Explanation

Enlarged main bearing clearance lets the crankshaft hammer against the shells, giving a low-frequency knock, and it also bleeds oil pressure. The oil pressure warning may appear at hot idle first.

Question 32Engine Mechanical Systems

What happens if a piston ring is filed with too small an end gap?

  1. The ring ends butt together and the ring may break Correct answer.
  2. Oil consumption rises sharply
  3. Compression drops steadily at idle
  4. The ring seals better as it heats up

Explanation

The gap is specified so the ring can expand as it heats. With insufficient gap the ends meet, the ring has nowhere to expand, and it either scuffs the bore or cracks.

Question 33Engine Mechanical Systems

What is the effect of a leaking intake manifold gasket on a port-injected engine?

  1. The exhaust becomes quieter and cooler
  2. Oil pressure drops at idle
  3. Extra fuel is drawn in and the mixture becomes rich
  4. Unmetered air enters and causes a lean mixture and rough idle Correct answer.

Explanation

Air drawn past a failed manifold gasket bypasses the airflow meter, so the ECU delivers fuel for less air than the engine actually receives. The result is a lean condition, unstable idle and often a lean fault code.

Question 34Engine Mechanical Systems

What does a variable valve timing phaser do?

  1. Changes valve spring rate with engine speed
  2. Advances or retards the camshaft relative to the crankshaft Correct answer.
  3. Alters the length of the intake runners
  4. Adjusts ignition timing at the distributor

Explanation

The phaser is an oil-pressure-controlled hub on the camshaft sprocket that rotates the cam a few degrees either way. This shifts valve events for better torque, economy and emissions at different speeds.

Question 35Engine Mechanical Systems

What is the job of the wastegate on a turbocharged engine?

  1. Prevents oil from reaching the turbine seal
  2. Bypasses exhaust gas around the turbine to limit boost Correct answer.
  3. Vents crankcase pressure into the intake
  4. Cools the charge air before it enters the engine

Explanation

The wastegate is a valve that opens to route exhaust gas past the turbine once target boost is reached. Without it, turbine speed and manifold pressure would keep rising until damage occurred.

Question 36Engine Mechanical Systems

Why is a cross-hatch pattern produced when honing a cylinder bore?

  1. To help retain oil and allow new rings to seat Correct answer.
  2. To reduce the bore to an exact size
  3. To harden the cylinder wall surface
  4. To increase the compression ratio slightly

Explanation

The intersecting scratches left by the hone hold an oil film on the bore and give the ring faces something to bed into during break-in. The angle must suit the ring type, and too rough or too smooth a finish causes oil use or poor seating.

Question 37Engine Mechanical Systems

Increasing valve overlap in a camshaft profile generally produces which effect?

  1. Lower idle vacuum and a power band shifted to higher rpm Correct answer.
  2. Reduced valve spring load at high engine speed
  3. No change in vacuum, only in peak valve lift
  4. Higher idle vacuum and stronger low-speed torque

Explanation

Overlap is the period when both valves are open around top dead centre, and widening it lets exhaust scavenging help fill the cylinder at high speed. At idle the same overlap allows exhaust gas back into the intake, lowering manifold vacuum and idle quality.

Question 38Engine Mechanical Systems

Which condition most directly promotes detonation in a spark-ignition engine?

  1. Ignition timing advanced beyond the knock limit Correct answer.
  2. Exhaust gas recirculation flowing at cruise
  3. A rich air-fuel mixture under load
  4. Coolant temperature below normal

Explanation

Detonation occurs when the end gas ignites spontaneously from rising pressure and temperature before the flame front arrives. Over-advanced timing raises peak pressure too early, and the knock sensor responds by retarding timing to protect the engine.

Question 39Engine Mechanical Systems

What is the purpose of the torsional damper fitted to the nose of the crankshaft?

  1. To hold the front crankshaft seal in place
  2. To absorb crankshaft torsional vibration Correct answer.
  3. To add rotating mass for a smoother idle
  4. To drive the oil pump through a gear

Explanation

Cylinder firing pulses twist and untwist the crankshaft, and at certain speeds this resonates. The damper's inertia ring and elastomer layer absorb that twist so the crank and the belt drive are not damaged.

Question 40Engine Mechanical Systems

On an interference engine, what usually happens if the timing belt breaks while the engine is running?

  1. The crankshaft snaps at the front journal
  2. The camshaft stops but the valves stay clear of the pistons
  3. Pistons strike the open valves and bend them Correct answer.
  4. The engine simply stalls with no internal damage

Explanation

In an interference design the valve and piston paths overlap, so valve timing must be maintained by the belt or chain. When the drive fails, the cam stops while the crank keeps turning and the pistons hit valves left hanging open.

Question 41Engine Mechanical Systems

A bore gauge shows a cylinder is 0.10 mm wider at the top than at the bottom, and the manufacturer's taper limit is 0.05 mm. What is the correct conclusion?

  1. Taper exceeds the limit, so the block needs reboring or replacement Correct answer.
  2. Fitting new piston rings alone will restore the bore
  3. The measurement is normal for a used engine
  4. A light hone will bring the bore back within size

Explanation

Taper is compared directly with the service limit before any repair decision. At double the limit the rings cannot follow the bore, so the cylinder must be bored or replaced rather than re-ringed.

Question 42Engine Mechanical Systems

Which component stores energy between power strokes and so smooths out the speed fluctuations of the crankshaft?

  1. Oil pump
  2. Flywheel Correct answer.
  3. Camshaft
  4. Connecting rod

Explanation

The flywheel is a heavy disc bolted to the crankshaft, and its inertia keeps the crank turning through the non-power strokes of the cycle. Energy absorbed during the power stroke is released during compression, intake and exhaust, giving steadier rotation.

Question 43Engine Mechanical Systems

What is the main purpose of the valve stem seal on an overhead valve engine?

  1. To retain the valve spring in its retainer
  2. To stop oil being drawn down the guide into the port Correct answer.
  3. To seal combustion pressure against the valve seat
  4. To lubricate the valve tip and rocker pad

Explanation

The stem seal wipes the valve stem and controls the small amount of oil that reaches the guide, so oil is not pulled into the intake port or pushed into the exhaust under manifold vacuum. It is a metering device, not a pressure seal.

Question 44Engine Mechanical Systems

An engine shows very high oil pressure on the gauge at all speeds, and the oil filter has started to seep at its crimp seam. Which fault best explains this?

  1. Engine oil heavily diluted by unburnt fuel
  2. A pressure relief valve stuck in the closed position Correct answer.
  3. An oil pickup screen partly blocked by sludge
  4. Main bearing shells worn beyond their clearance limit

Explanation

A positive-displacement oil pump will keep raising pressure until the relief valve opens, so a valve jammed shut lets pressure climb until gaskets and the filter can are stressed. The filter seeping confirms the pressure is genuinely high rather than a gauge error.

Question 45Engine Mechanical Systems

On an engine with a closed crankcase ventilation system, a PCV valve stuck in the closed position will most likely cause which condition?

  1. Unmetered air enters the intake and the idle speed rises
  2. Pressure builds in the crankcase and oil is forced past seals Correct answer.
  3. Crankcase pressure falls below atmospheric and seals draw air in
  4. Oil mist is drawn into the intake and burned during combustion

Explanation

Blow-by gas is produced continuously, and the PCV valve is the metered path that lets it be drawn into the intake. With that path blocked, the gas pressurises the crankcase until it escapes through seals, gaskets and the dipstick tube.

Question 46Engine Mechanical Systems

On a high-mileage engine, a dull metallic knock is heard from the cylinder bores for the first minute or two after a cold start and then fades as the engine warms. Which is the most likely cause?

  1. Excessive piston-to-bore clearance Correct answer.
  2. Excessive valve clearance on the mechanical rockers
  3. A leaking exhaust manifold gasket
  4. Worn main bearing shells

Explanation

A worn bore and piston skirt leave an oversize clearance that lets the piston rock and slap while it is still cold and small. As the piston expands with heat the clearance closes up, so the noise fades, which is the signature of piston slap.

Question 47Engine Management, Fuel and Emission Systems

The stoichiometric air-fuel ratio by mass for gasoline is closest to which value?

  1. 14.7:1 Correct answer.
  2. 24.0:1
  3. 17.2:1
  4. 9.8:1

Explanation

Complete combustion of gasoline occurs at roughly 14.7 parts air to 1 part fuel by mass. The ECM treats this ratio as the target during closed-loop fuel control. Lower numeric ratios are rich mixtures and higher ones are lean.

Question 48Engine Management, Fuel and Emission Systems

Which sensor directly measures the mass of air entering the engine?

  1. Manifold absolute pressure sensor
  2. Mass airflow sensor Correct answer.
  3. Throttle position sensor
  4. Intake air temperature sensor

Explanation

A mass airflow sensor measures the actual mass of air passing through the intake, which the ECM converts directly into a fuel mass requirement. A MAP sensor infers airflow indirectly from pressure and speed.

Question 49Engine Management, Fuel and Emission Systems

Which three exhaust gases is a three-way catalytic converter designed to treat?

  1. Carbon dioxide, water vapour and nitrogen
  2. Sulphur dioxide, carbon monoxide and unburnt hydrocarbons
  3. Nitrogen, oxygen and unburnt hydrogen
  4. Carbon monoxide, hydrocarbons and oxides of nitrogen Correct answer.

Explanation

A three-way catalyst oxidises carbon monoxide and hydrocarbons while simultaneously reducing oxides of nitrogen. Efficient operation requires the mixture to oscillate close to stoichiometric. Carbon dioxide, water and nitrogen are the harmless products it creates.

Question 50Engine Management, Fuel and Emission Systems

What is the primary function of the positive crankcase ventilation system?

  1. To reduce intake air noise at idle
  2. To increase fuel pressure during cold start
  3. To route blow-by gases back into the intake Correct answer.
  4. To cool the engine oil during sustained high load

Explanation

Blow-by gases escape past the piston rings into the crankcase and carry unburnt hydrocarbons. The PCV system draws these gases into the intake so they are burned instead of vented. This also prevents crankcase pressure from building up and forcing oil past seals.