HSC Automotive (VET) cheat sheet

Four-stroke cycle order: intake, compression, power, exhaust; the crankshaft completes two revolutions per full cycle in a four-stroke engine.

Stoichiometric air-fuel ratio for petrol is about 14.7:1 by mass; rich mixtures have excess fuel, lean mixtures have excess air.

Torque wrench settings are specified dry or lubricated; applying a lubricated spec to dry threads over-tensions the fastener and can stretch or snap it.

Battery capacity: cold cranking amps (CCA) rate starting ability at -18 °C, while amp-hours (Ah) rate reserve capacity; they are not interchangeable figures.

Brake fluid is hygroscopic and absorbs moisture; DOT 3 and DOT 4 are glycol-based and must not be mixed with DOT 5 silicone fluid.

Tyre placard pressure is set cold; pressure rises with heat, so checking hot tyres and bleeding to placard pressure leaves them under-inflated.

A vehicle hoist must be rated for the load and the lifting points must sit on the manufacturer's designated jacking and support locations.

Diagnostic trouble codes (DTCs) identify a circuit or system fault, not a failed component; the code is a starting point for testing, not a diagnosis.

Personal protective equipment for automotive work includes safety glasses, steel-capped boots, gloves, and hearing protection where noise exceeds the workplace exposure standard.

A fire extinguisher for flammable liquids is class B; dry chemical or foam suits fuel and oil fires, and water must not be used on a fuel fire.

Battery charging releases hydrogen gas, which is explosive; charge in a ventilated area and keep sparks, flames, and smoking away from the battery.

A material safety data sheet (SDS) must be available for every hazardous chemical in the workplace and lists first-aid and spill-response information.

A hazard is a source of potential harm; a risk is the likelihood and consequence of that harm occurring, so risk is assessed after the hazard is identified.

Waste oil, coolant, and solvents are controlled wastes and must go to licensed recyclers, not to drains, soil, or general rubbish.

A vehicle should not be raised on a jack alone; axle stands or a hoist must support the load before any part of a person goes under it.

Manual handling risk is reduced by team lifting, mechanical aids, and keeping the load close to the body rather than by relying on technique alone.