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Used Car Inspection Checklist: 30 Things to Check Before You Buy

2026-05-13 · 9 min read

An honest mechanic charges $150-$250 for a pre-purchase inspection. Most of what they're looking for, you can spot yourself in 20 minutes if you know where to look. Here's the same 30-point walkaround a good Aussie mechanic uses, structured so you can run it in front of the seller without missing anything.

Before you turn up: do this first

The single most valuable five minutes you'll spend on a used car purchase happens before you leave the house. Run a vehicle history check on the rego or VIN the seller has shared. If the report flags finance owing, a written-off record, or a stolen status, you save yourself the drive - and the awkward conversation. An Essentials PPSR + NEVDIS check at $19.99 takes about 60 seconds and is the only way to verify the vehicle is what the seller says it is, on paper.

Confirm three things over the phone before you book the inspection:

  1. That the seller is the registered owner (not a friend, family member, or "I'm helping them sell it"). Mismatched ownership is a classic curbsider tell.
  2. That the rego matches the VIN, and both match what's on the ad. Mismatch = walk.
  3. That you can inspect the car at the registered address during daylight hours. "Meet at the shopping centre carpark" is a red flag - legitimate sellers have no reason to avoid showing you where the car lives.

The 30-point walkaround

Exterior (8 checks)

  1. Panel gaps. Stand at each corner of the car and look down the side. Bonnet, doors, boot, and bumper gaps should be uniform within ~2 mm. Inconsistent gaps mean panel replacement - often from collision repair the seller forgot to mention.
  2. Paint match. Crouch and view each panel from a shallow angle. Slight texture or colour shift between panels = re-spray. Look for over-spray on rubber seals, plastic trim, and inside the door jambs - telltale of a budget body shop.
  3. Rust under the doors and wheel arches. Run your fingers along the seam where the door meets the sill, and inside the wheel arch lip. Bubbling paint here is structural rust starting underneath - expensive to fix properly, easy to hide with filler.
  4. Tyre tread depth (all four). The legal minimum is 1.5 mm but the practical minimum for safety is 3 mm. Use the raised wear indicators inside the tread groove. Uneven wear across one tyre (more on inside or outside edge) means suspension alignment is out - usually because of a kerb strike or worn bushings.
  5. Tyre brand match. Four tyres of the same brand and date code means a recent set; a mix of brands or wildly different wear levels means a cheap-out replacement. Check the date code (a 4-digit number in an oval, format WWYY - "2825" means week 28 of 2025).
  6. Windscreen chips and cracks. A chip in the driver's sight line fails roadworthy inspection in every Australian state. A crack over 150 mm or anywhere on the wiper sweep is also a fail.
  7. Light operation. Have someone press every light - headlights (low and high beam), brake lights, indicators, reverse, fog. Yellowed or hazed headlight lenses are a $50 polish fix but signal years of UV exposure (and possibly a long-parked car on a driveway, not a garaged one).
  8. Boot floor and spare-wheel well. Lift the boot carpet and the spare-wheel cover. Look for ripples, weld marks, or fresh-looking sealant - signs of rear-end repair the body panels hide. The boot well should be the same factory paint colour underneath the spare.

Interior (6 checks)

  1. Driver's seat wear vs odometer. A car claiming 90,000 km should not have a worn-through driver's seat bolster, a smooth steering wheel grip, or pedal rubbers worn to bare metal. A cabin that looks 200,000 km on a 90,000 km odometer is a strong rollback flag - we cover odometer fraud in detail here.
  2. Carpet smell and dampness. Press the carpet in the driver's footwell and the rear footwells. Any squelch or musty smell = water ingress, either from a leaking sunroof, a windscreen seal, or (worst case) flood damage. Always check both rear footwells - flood water settles low.
  3. All electrics. Try every button: windows (each one, both directions), mirrors, central locking, AC fan speeds, AC vent direction, cruise control, audio (try Bluetooth pairing), reverse camera, parking sensors. Anything that doesn't respond is a deduction from the price.
  4. Air conditioning blast test. Engine running, AC on max, hold a thermometer (or a phone with a thermometer app) to the centre vent. Cold should be ≤ 10 °C in under 90 seconds; if it hovers around 18 °C, the regas is borderline ($200-$400) or the compressor is failing ($1,500+).
  5. Dashboard warning lights at ignition. Sit in the car, key on but engine off. Note every warning light. Start the engine and watch which lights go out within 5 seconds. Anything still illuminated - especially the engine, ABS, airbag, or DPF light - is a real fault the seller knows about.
  6. Service logbook. The logbook should show service stamps at the manufacturer-specified intervals. Gaps of > 18 months or > 25,000 km between services flag a car that wasn't maintained. A logbook with stamps only from "Greg's Mobile Mechanic" and no franchise stamps doesn't disqualify the car but changes the negotiation position.

Engine bay (6 checks)

  1. Engine bay cleanliness. Too clean = freshly detailed to hide leaks. Too filthy = neglected. Look for the Goldilocks zone: dust and road grime, but no oil weeping from gasket seams.
  2. Oil dipstick. Engine warm, off for 5 minutes. Wipe the dipstick on a paper towel, re-dip, read the level (should be between min and max) and the colour (honey amber = recent change; charcoal black = overdue but not catastrophic; milky or frothy = coolant in oil = head gasket failure, walk away).
  3. Coolant reservoir. Should be at or near the MAX line, the correct colour for the make (Toyota red, Holden green, Ford orange, VW pink - manufacturer-specific). Rusty water or a brown sludge in the reservoir indicates corrosion or a blown head gasket.
  4. Brake fluid reservoir. Clear yellow-amber = fine. Dark brown or black = overdue change (every 2 years per most manufacturers); replace immediately after purchase but not a walk-away.
  5. Battery age. Stamped on the battery casing. Australian batteries average 3-5 years; anything over 5 years is on borrowed time. A 2-year-old battery in a car the seller claims has been "running fine" suggests recent jump-starts and a possible charging-system problem.
  6. Cold-start smoke. Ask the seller to bring you to the car with the engine cold (not pre-warmed). When you turn the key, watch the exhaust pipe from the rear. White smoke that doesn't clear within 30 seconds = coolant in the combustion chamber (head gasket). Blue smoke = oil burning (worn valve seals or piston rings). Black smoke = over-fuelling (injector or air-flow fault).

Underbody + test drive (10 checks)

  1. Walk around the car and look underneath. Fresh oil drips on the ground where the car was parked = oil leak. Wet patches on suspension components or steering rack ends = power steering fluid loss or shock absorber failure.
  2. Exhaust system. Rust holes in the exhaust cause MOT/roadworthy failures and are 5-minute walk-aways at inspection time.
  3. Cold-engine idle. From a cold start the idle should settle to its target RPM (usually 700-900) within 30 seconds. Hunting (bouncing up and down) means an air-leak or sensor fault.
  4. Reverse out. Try the reverse gear - should engage cleanly without grinding (manual) or shudder (auto). Watch the mirrors - does the rear of the car drop when you reverse? That's a clutch or trans mount issue (auto only).
  5. Steering. Drive at 40 km/h through a smooth stretch and take both hands off the wheel for 2 seconds. The car should track straight; pull to either side = alignment out (cheap fix) or suspension damage (not cheap).
  6. Brakes from 60 km/h. Find an empty stretch of straight road. Brake firmly (not panic-hard) from 60 km/h. The car should stop straight. Pulling left or right = sticking caliper or warped rotor. Pulsing through the pedal = warped rotors, $400-$800 to fix.
  7. Highway test. Get to 100 km/h and listen for drone or vibration from the wheels (wheel-bearing wear), or a whining from the transmission (gear-set wear).
  8. Manual gearbox cold and hot. Cycle through every gear - 1st through 6th and reverse - both from cold and again after 15 minutes of driving. A synchro that's worn engages fine cold and crunches hot, so the cold-only test fools many buyers.
  9. Auto kickdown. From 60 km/h, mash the accelerator. The auto should kick down within 1 second and shift cleanly. Hesitation, flare-up (RPMs surge before shift completes), or jolts means transmission wear - repair bills start at $3,500.
  10. Park and look at the temperature gauge. After the test drive, park and watch the gauge for 5 minutes. Climbing past the half mark while idling = cooling-system fault (radiator, thermostat, water pump). Cars overheat in driveways, not on highways - the airflow at speed cools an under-spec system.

The paperwork moment

Five minutes of paperwork can save you the entire purchase price. Before you transfer any money:

  • Confirm the rego on the car physically matches the rego on the licence the seller is showing you. People do attach fake plates.
  • The VIN on the dashboard (visible through the windscreen) and the VIN on the door pillar (open the driver's door, look at the metal plate riveted to the B-pillar) must match each other and the rego paperwork. A mismatch between the two VINs on the car itself is a re-birthed vehicle - walk away immediately and report to the state authority.
  • Run a final history check on the day of purchase. Encumbrances can be registered in real time - a check you ran two weeks ago doesn't protect you. Our reports are rerunnable anytime from your dashboard.

What this checklist won't catch

Three categories of fault are invisible without specialist equipment:

  • Computer fault codes. Many modern issues trigger a code in the engine ECU that doesn't yet illuminate the dashboard warning light. A mechanic with an OBD-II scanner reads these in 30 seconds. If you suspect the seller has cleared codes to hide a fault, a pre-purchase OBD scan ($60-$100) is worth it.
  • Compression testing. Detects worn piston rings and burnt valves long before they show symptoms. Requires the spark plugs to come out - not a roadside test.
  • Suspension bushing condition. Visual inspection misses ~50% of failed bushings. A mechanic on a hoist with a pry bar reveals the rest.

For any car over ~$25,000 we recommend booking a pre-purchase inspection at a workshop you trust (not one the seller suggests). You bring the checklist, the workshop brings the scanner and the hoist - together you catch ~95% of pre-purchase risks.

Bottom line

The full 30-point walkaround is 20 minutes of work. Combined with a $19.99 Essentials report or $29.99 Comprehensive report, you'll know more about the car than the seller does - and that's the position to negotiate from.