DGT C licence questions: Mechanics and maintenance

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Question index View topic Practise Mechanics and maintenance

A lorry has an expansion tank marked MIN and MAX. When checking coolant with a cold engine according to the manufacturer’s instructions,…
In a combustion engine with a turbocharger and intercooler, where is the intake air filter located?
On a road surface in good condition, the steering wheel vibrates particularly at certain speeds. Which of these mechanical causes may…
On ice, up to what multiple of the normal braking distance on a dry road may a vehicle need?
A lorry travels at night, between sunset and sunrise, on an insufficiently lit road through a built-up area. Which lights must it use?
What does adjusting the headlights of your lorry's lighting system involve?
Which statement about braking distance on an icy road compared with a dry road at the same speed is correct?
To check a lorry’s oil level with the dipstick, its manufacturer specifies checking before starting, with a cold engine and the vehicle on…
In a flooded lead-acid battery with vented caps, what are the vent openings for?
If you keep your vehicle's tyres at the correct pressure, you will ensure that...
In a lorry with pneumatic brakes equipped with an air dryer, which device removes moisture from compressed air to reduce the risk of…
If you anticipate needing to slow down, which behaviour supports efficient driving without compromising safety?
When the tyre inflation pressure of your truck is higher than recommended...
What is the purpose of a heat exchanger mechanism or intercooler?
If the driver of a lorry observes that a vehicle has indicated its intention to turn left, may they overtake it on the right?
One of the factors that affects driving safety is...
If, when operating the direction indicator, the warning lamp flashes faster than normal, this indicates that...
If a warning appears in a C1 or C truck indicating a major fault, the correct action is to:
A lorry will overtake a cyclist outside a built-up area on a road with one lane in each direction. What minimum lateral separation must it…
When overtaking a car with a lorry, what safe lateral separation must be left?
What type of oil is a lubricant classified SAE 15W-40?
A lorry has hydraulic power steering with a reservoir marked MIN and MAX. Should its fluid level be checked?
In a lorry diesel engine, what may abnormal black exhaust smoke be associated with?
A lorry has a battery master switch. If the instrument panel receives no power when the ignition is switched on, what initial check…
In a lorry with a synchronised manual gearbox, does unnecessary double-declutching with extra throttle blips and slower shifts support…
In a diesel engine with a conventional turbocharger lubricated by the engine oil circuit, what oil lubricates its bearings?
A steering fault in a C1 or C truck:
How is the normal operating temperature of an engine’s coolant determined?
If a road vehicle’s tyres, when cold, have less pressure than specified by the manufacturer for its load and use...
In efficient driving with a manual synchronised gearbox in good condition, why avoid unnecessary double-declutching?
What is a lubricating oil with SAE 15W-40 specification?
If, due to traffic requirements, a truck with a maximum authorised mass (MAM) of more than 3,500 kg becomes immobilised inside an…
You park a 4,000 kg MAM lorry on a significant uphill gradient and leave the seat. In addition to stopping the engine, disconnecting the…
What is the function of the oil filter?
When checking a lorry’s engine oil level with the dipstick under manufacturer instructions, on what ground should it be parked?
At the same speed, which driver-related factor can increase the distance travelled from perceiving danger until braking begins?
While driving your lorry, you notice that it veers towards one side of the carriageway only when you press the brake pedal. What could this…
What are the crankshaft surfaces that rotate in the engine block’s main bearings called?
A liquid-cooled lorry has an expansion tank marked MIN and MAX. When checked under manufacturer instructions, how should the level be?
To compare and adjust lorry tyre pressure to the recommended cold value for its load, when should it be checked?
In a worm-gear steering system, how does the steering wheel return to its rest position (straight-ahead line)?
Other conditions being equal, how may tyre pressure below the recommendation for the load affect fuel consumption?
A lorry has an operational electric retarder and descends a steep gradient with suitable grip. Under manufacturer instructions, how should…
A breakdown leaves a lorry immobilised on the carriageway or shoulder of an insufficiently lit through-road within a built-up area, between…
On a vehicle with a hydraulically actuated clutch, where should fluid level be checked following manufacturer instructions?
With a small tread puncture where the object remains embedded, which tyre usually loses air more slowly than a tyre with an inner tube?
In a combustion-engine vehicle with electronic injection that does not require accelerator input to start, which practice avoids…
What is the “fading” effect that a vehicle's brakes can suffer from?
In a combustion engine with a turbocharger and intercooler, where is the intake air filter located?
Before driving a truck, which option includes checks of its safety systems rather than only fuel or cleanliness?
A lorry driver sees the vehicle ahead clearly indicating its intention to turn left. If no other rule or sign prohibits it, may the lorry…
Two batteries, each with a nominal voltage of 12 V, are correctly connected in series so that their voltages add. What is the combination’s…
An insulated vehicle has a mechanical-compression or absorption refrigeration unit that lowers and maintains its body temperature. Which…
Should you periodically check the level of the windscreen washer fluid?
If a vehicle's steering system shows unstable behaviour and pulls to one side, what should we check?
In an internal-combustion engine, what does persistent bluish-white exhaust smoke associated with high oil consumption usually indicate?
If the lorry I am driving has a hydraulically operated braking circuit, I must...
When the shock absorber deteriorates and loses effectiveness over time, how does this affect the suspension?
What does the word “TUBELESS” written on the side of the tyre indicate?
If an exhaust silencer is broken and no longer properly attenuates engine noise, what effect does this have?
What properties should a gearbox gear lubricant have?
In a conventional four-cylinder, four-stroke engine, how far does the crankshaft rotate during one complete piston stroke from one dead…
By definition, a heated lorry is a motor vehicle that is:
While driving your lorry, you notice that it veers towards one side of the carriageway only when you press the brake pedal. What could this…
As a general rule, stopping on urban roads shall be carried out by positioning the vehicle…
In an electrical diagram with two identical compatible 12 V nominal batteries suitable for series connection, which link gives 24 V nominal…
What should I do to drive efficiently?
If you are driving your lorry downhill, can you put it in neutral to save fuel?
At the same speed and with the same lorry, a wet road reduces grip compared with a dry road. If you do not intend to overtake, how should…
Fog significantly reduces visibility. In addition to the compulsory position lights, may you use dipped headlights without switching on the…
One of the components that forms part of the pneumatic braking system is...
At the same speed and with the same vehicle, a wet road reduces grip compared with a dry road. What happens to braking distance?
Among the different systems that make up a vehicle's engine, which one does the catalytic converter belong to?
Under comparable driving conditions, which tyre condition tends to increase fuel consumption?
Passive safety systems are...
If you notice a major fault in the brakes or steering of a C1 or C truck, the correct action is to:
In the tyre marking 385/65 R22.5, what does the number 22.5 indicate?
What maintenance should we carry out on the cooling system?
What benefit is supported by keeping lorry tyres at the recommended cold pressure for their load?
Which of the following parameters affects the adjustment of the driver's seat?
In a C1 or C truck, correct tire pressure:
Under comparable conditions and as a general rule, tyre grip is usually lower when driving on…
In a conventional system whose coolant pump is belt-driven from the engine, which component supplies movement to that belt?
The driver of a lorry with a MAM exceeding 3,500 kg must leave the driving position when parking on a steep upward slope with a kerb. If…
Light rain does not significantly reduce visibility. There is no fog, smoke, dust or other visibility-reducing condition, and you are not…
In a cooling circuit designed to operate under pressure, what effect does increased pressure have on the boiling temperature of the same…
After passing through a puddle, your lorry’s brakes may be wet. When it is safe to check, which operation should you verify especially?
If you notice unusual noises or vibrations in a C1 or C truck, the prudent action is to:
Between sunset and sunrise, you drive a lorry on a sufficiently lit road through a built-up area. Besides position lights, which headlights…
With the same oil and engine speed, other factors being equal, which oil condition can favour lower pressure by reducing its viscosity?
If a warm engine persistently emits bluish exhaust smoke, what may this indicate?
Will I need to carry out any special maintenance if my vehicle's engine uses a timing belt drive system?
A combination of vehicles consisting of a motor vehicle coupled to a semi-trailer is known as:
The manufacturer specifies a 12 V system using two compatible 12 V batteries connected in parallel. How are their terminals linked in that…
In a lorry’s friction clutch with a manual gearbox, which component is pressed against the flywheel to transmit engine rotation to the…
On a long descent, what can you do to stop the vehicle from gradually gaining speed?
In a conventional manual gearbox and bevel-gear differential, what lubricant is normally used for the gears, respecting each unit’s…
On a road surface in good condition, the steering wheel vibrates particularly at certain speeds. Which of these mechanical causes may…
Can a manufacturer-specified and integrated electromagnetic retarder operate in a vehicle equipped with ABS?
A heat-exchanging mechanism, or intercooler, achieves...