SKM Motor Vehicle Mechanic Level 3 key terms

Wearable gear such as safety glasses, gloves, hearing protection, and steel-toe boots that reduces a worker's exposure to hazards. Employers must supply it free and train staff in its correct use and limitations.

The systematic process of spotting conditions or actions in a workshop that could cause injury, ill health, or damage before work starts, so controls can be applied and recorded.

A written breakdown of a task into sequential steps, with the hazards of each step and the controls required. It is reviewed with the technician before starting unfamiliar or high-risk work.

A procedure for isolating energy sources, such as battery leads, high-voltage systems, or compressed air, with locks and warning tags so equipment cannot be re-energised while someone is working on it.

Work practices for hybrid and electric vehicles: identifying orange-coded cables, de-energising the pack, verifying absence of voltage, using insulated tools, and never assuming a vehicle is safe because it is silent.

A standardised document listing a chemical product's hazards, safe handling, storage, first-aid measures, and disposal requirements. It must be accessible to every worker who handles the substance.

Separating waste streams such as used oil, coolant, brake fluid, solvents, and lead-acid batteries into correctly labelled containers so each can be recycled or disposed of lawfully without contaminating others.

Removing refrigerant from an air-conditioning system into a suitable container rather than venting it to atmosphere. It is a legal requirement and protects the ozone layer and climate.

A wrench that releases or signals at a set tightening force, used where fasteners must be tightened to a manufacturer's specification. It must be stored at its lowest setting and calibrated periodically.

A precision measuring instrument with a calibrated screw and spindle, used to measure outside dimensions such as shaft or journal diameter to hundredths of a millimetre. It is checked against a standard before use.

A gauge with a spring-loaded plunger and needle that shows small linear displacements, used for measuring runout, end play, and backlash when mounted on a magnetic base.

A set of thin metal blades of known thickness used to check clearances such as spark plug gaps, valve lash, and ring end gap by finding the blade that fits with slight drag.

A fastener tightened past its elastic limit by a specified angle after reaching a torque figure. It stretches permanently and must be replaced rather than reused whenever it is loosened.

A diagnostic measurement of peak cylinder pressure with the engine cranked and the throttle open. Comparing readings across cylinders reveals worn rings, leaking valves, or a blown head gasket.

A test that supplies compressed air to a cylinder at top dead centre and measures the percentage lost. Listening at the intake, exhaust, or oil filler locates the leaking component.

The designed gap between the valve stem and its actuating rocker or cam follower. Too little clearance prevents full seating and burns valves; too much causes noise and reduced lift.

The sealing layer between the cylinder head and block that contains combustion pressure and separates coolant and oil passages. Failure causes overheating, coolant loss, or white exhaust smoke.

An exhaust-driven turbine that spins a compressor to force more air into the engine. It needs clean oil supply and a cool-down period to avoid carbonised bearings and shaft damage.

A valve that bypasses exhaust gas around the turbine once boost pressure reaches a set level, protecting the engine from over-boost. It may be controlled by a spring actuator or electronically.

A filter in the exhaust that traps soot from diesel combustion. It is cleaned by passive or active regeneration at high temperature, and becomes blocked by short, cold running cycles.

A system that returns a measured portion of exhaust gas to the intake to lower combustion temperature and reduce nitrogen oxide emissions. Carbon build-up is a common fault.

A condition where engine speed rises without matching vehicle speed because the clutch disc cannot transmit full torque. Causes include a worn friction disc, weak pressure plate, or oil contamination.

The small clearance between the release bearing and the pressure plate fingers that ensures the clutch stays fully engaged when the pedal is released. Excess play causes incomplete disengagement.

A flywheel split into two masses joined by springs and a friction damper to absorb torsional vibration. It cannot be resurfaced like a solid flywheel and is replaced when play exceeds limit.

A fluid coupling in automatic transmissions that multiplies engine torque at low speed through a stator and allows the vehicle to idle in gear without a mechanical clutch.

Verifying automatic or manual gearbox oil against the manufacturer's procedure, often with the engine running and fluid at a specified temperature, since overfilling and underfilling both cause damage.

A joint that transmits drive through a varying angle at uniform speed, used on driveshafts. A split boot lets grease escape and grit enter, producing clicking on turns.

Adjustment of camber, caster, and toe so wheels point within manufacturer specification. Incorrect alignment causes uneven tyre wear, pulling, and off-centre steering.

Correcting uneven mass distribution around a wheel by adding weights so it spins without vibration at road speed. Imbalance shows as steering shimmy or seat vibration.

The measured height of tread blocks above the grooves, checked with a gauge. Below the legal minimum, water cannot be cleared and wet grip falls sharply.

Loss of braking force when heat builds in pads and fluid, causing friction to drop or fluid to vaporise. It is managed by cooling, correct fluid, and smooth driving technique.

The temperature at which brake fluid vaporises and creates a compressible gas bubble in the hydraulic circuit. Moisture absorption lowers it, so periodic replacement is specified.

A system that modulates brake pressure at each wheel to prevent lock-up and preserve steering during hard braking. Wheel speed sensors and a hydraulic unit are its key components.

The relationship stating voltage equals current multiplied by resistance. Technicians use it to calculate expected circuit values and to interpret voltage drop measurements during diagnosis.

Measuring the potential difference across a conductor or connection while current flows. Excess drop reveals high resistance from corrosion or a poor earth, which ordinary voltage checks miss.

Current that continues to flow from the battery after all systems should have shut down, flattening it overnight. It is found by measuring current and removing fuses one at a time.

A diagnostic device that communicates with vehicle control modules to read fault codes, live data, and actuator tests. It guides diagnosis but never replaces physical verification of the fault.

A stored code identifying the circuit or system where a control module detected a fault. It narrows the search area but does not by itself name the failed component.

A two-wire serial bus that lets control modules exchange data without dedicated wiring for each signal. Bus faults or incorrect termination can disable many unrelated systems at once.

An instrument that analyses the gas in an air-conditioning system to confirm its type and purity before recovery or charging, preventing cross-contamination of recovery equipment.

The temperature of refrigerant vapour above its saturation point at a given pressure. It confirms the evaporator is fully evaporating liquid and is used to judge charge and expansion valve operation.

The temperature of liquid refrigerant below its saturation point at a given pressure, measured at the condenser outlet. It indicates whether the system holds the correct charge.

A structured check performed before a vehicle is handed to its owner, covering fluids, tyre pressures, function tests, software status, and documentation, with results recorded on a signed checklist.

A controlled drive after repair to confirm the fault is resolved and no new symptoms appeared, performed within legal and safety limits and documented on the job record.

A second-person or self-check confirming that specified measurements, torque values, and function tests meet standard before the vehicle is released, with the checker's name recorded.

The working document for a repair, listing the customer's complaint, authorised work, parts, labour time, and technician notes. It forms the legal and commercial record of the transaction.

Reproducing or confirming the reported symptom before diagnosis, ideally with the customer or a road test, so that work addresses the real fault rather than an assumption.

Advising the customer of additional needed work, with evidence and priority explained honestly. Recommendations must be authorised before work proceeds and never presented as already mandatory.

A short, focused briefing at the start of a shift covering a specific hazard, task, or lesson learned. It is recorded and kept brief so the message is retained.

Teaching a task in the real workplace through demonstration, guided practice, and observation, with competence confirmed against a checklist before the trainee works unsupervised.