Pre-Purchase Inspection: Inspection Checklist Before You Buy

The short version

A proper pre-purchase inspection takes about 90 minutes to two hours. It covers four areas: under the bonnet, underneath, body and interior, and on the road. Within those four areas, we run a detailed checklist looking for everything from obvious problems (low oil, worn brakes, leaking radiator) to less obvious ones (signs of previous accident repair, hidden frame damage, transmission early-warning signs).

The inspection produces a written report with photos, emailed to you the same day. You use the report to walk away, to renegotiate the price, or to buy with confidence. In our experience the inspection often saves the buyer money — sometimes a few hundred dollars in renegotiated service work, sometimes thousands in walk-away calls on cars that turn out to have major hidden issues.

This article walks through every item on the checklist, what we are looking for, and what each finding usually means for the buy decision.

Under the bonnet (8 checks)

1. Engine oil condition

We pull the dipstick, look at the colour, smell it, feel it between our fingers. Clean oil is amber to light brown. Black oil that has been there too long is normal-ish. Milky beige oil is bad news (coolant contamination, almost always a head gasket). Oil with a burnt smell points to overheating in the engine's past.

2. Coolant level and condition

The coolant reservoir should be between MIN and MAX. The colour should be the manufacturer's specified colour (green, pink, orange depending on the make) and should be clear, not rusty. Rusty coolant means the system has not been maintained. Bubbles or oil floating on the coolant is a head gasket warning.

3. Engine leaks

We look at every external surface of the engine for fresh oil, fresh coolant or fresh transmission fluid. Common leak points: valve cover gaskets, oil pan, front and rear main seals, timing cover, water pump, hoses. We note whether a leak is active (wet) or old (dry, dusty residue).

4. Drive belt and tensioner condition

The auxiliary drive belt should be tight, with no cracks, glazing or fraying. The tensioner should hold tension without wobble. A belt nearing failure usually means a $150 to $300 replacement job, which is fine if you knew it was coming, less fine if you find out at 80 kilometres an hour on the motorway.

5. Battery age and condition

Most batteries last three to five years. We check the date code on the battery (a sticker, or sometimes a stamp on the casing), test the state-of-charge with a digital tester, and test the state-of-health under load. A battery on the way out is rarely a deal-breaker, but it should come off the asking price.

6. Air filter

Pop the airbox, check the filter. A heavily clogged filter is a quick service issue but it tells you about how the car has been cared for. Clean filter = serviced regularly. Filter full of dust and dead leaves = neglected.

7. OBD diagnostic scan

We connect a professional scan tool and read every available control module. Stored fault codes. Pending fault codes. Historical codes from the last few drive cycles. Freeze-frame data. A car with a clean scan tool has either been well-maintained or has had its codes cleared right before sale (which is itself a flag, and we can usually tell the difference).

8. Engine bay overall

A general look at how the engine bay has been treated. Aftermarket additions (turbos, plug-in performance modules, unauthorised wiring) are usually flags. A spotlessly clean engine bay on an older car is sometimes a flag too, because excessive cleaning hides leaks.

Underneath (10 checks)

9. Transmission and drivetrain

Visual check for transmission fluid leaks. If the transmission is the type with a dipstick, we check the fluid level and condition (should be pink-red, not brown, not burnt-smelling). On constantly-variable transmissions (CVTs), we check the inspection bolt where available. CVTs are particularly sensitive to neglect.

10. CV joints (front-wheel-drive cars)

The constant-velocity joints transmit drive from the differential to the wheels. They have rubber boots filled with grease. We check the boots for splits, tears or missing clamps. A torn boot is a $250 to $450 fix if caught early, or a $600 to $1,200 fix if it has been torn long enough to ruin the joint.

11. Differential and transfer case (4WDs)

On 4WDs and AWDs, we check the differential housing for leaks and feel the differential oil at the filler plug for water contamination. Towing-heavy diesels are especially prone to differential wear.

12. Suspension front and rear

We grab each suspension component and check for play: lower ball joints, upper ball joints, tie-rod ends, sway-bar links, sway-bar bushes, shock mounts. We push down on each corner of the car and watch how it settles (one bounce is healthy, three or four bounces means worn shocks).

13. Steering rack and components

The steering rack should have no play at the inner tie-rod ends. The power steering should be quiet at full lock. Power-steering fluid should be at the right level and not dark or burnt.

14. Brakes (all four corners)

We measure brake pad thickness at all four corners with a depth gauge, not just visual estimation. We measure rotor thickness with a micrometer and compare it to the manufacturer's minimum. We check the brake hoses for cracks and the calipers for fluid leaks. We test the parking brake.

15. Exhaust system

A look along the full length of the exhaust system for rust, holes, hangers, leaks, and signs of repair welding. A heavily-patched exhaust is not a deal-breaker but it indicates ongoing problems.

16. Catalytic converter

The catalytic converter sits in the exhaust system. We check its colour (overheating shows as discolouration) and tap it gently to listen for rattling (a broken honeycomb inside). A failed catalytic converter is a $1,500 to $3,500 replacement on most cars.

17. Underbody rust

We check chassis rails, jacking points, subframes and any seams where water sits. Coastal cars and older 4WDs are the highest risk. Surface rust is normal. Structural rust (rust through the metal, rust on a chassis rail, rust at a suspension mount) is usually a walk-away.

18. Signs of accident repair

Underbody panels that have been replaced, welds that do not match the factory, paint overspray on suspension components, mismatched fasteners. These are signs the car has been in a bigger accident than the seller is letting on. Not necessarily a deal-breaker (a well-repaired accident car can still be sound), but it should come off the price and you should know about it.

Body and interior (5 checks)

19. Panel alignment

Every panel gap (between door and body, bonnet and guard, boot and quarter panel) should be even on both sides of the car. Uneven gaps usually mean accident damage that has been straightened but not perfectly. We use a panel gap gauge for the front and rear.

20. Paint condition

We look at every panel for overspray, colour mismatch under direct sunlight (or under a paint thickness gauge if needed), and the texture of the paint. Factory paint has a consistent orange-peel texture. Repainted panels are usually slightly different.

21. All electrics

We test every light (headlights low and high, indicators front and rear, brake lights, reverse lights, fog lights), every power window, the central locking, the wipers including the rear if equipped, the horn, the cluster lights, the radio, the reversing camera, the parking sensors. The air-con cold-test is a simple "does it blow cold" check. Anything more involved on an air-con system is outside our scope and we note it for follow-up by a specialist.

22. Interior condition

Seat condition (rips, sagging, stains, bolster wear that suggests heavy driver use). Seat-belt operation (every belt should retract properly and lock under sudden pull). Dashboard for any warning lights that come on at start-up but should go out. Mileage on the odometer cross-checked against the service history.

23. Airbag history

The airbag warning light should illuminate at start-up and then go out within a few seconds. A light that stays on means a stored fault. A light that does not illuminate at all is often an indicator of tampering (someone hiding a fault by disabling the bulb). We pull the airbag system codes with the scan tool to check for any deployed-airbag history that has not been disclosed.

On the road (5 checks)

24. Cold start and warm-up

We start the car cold (this is one reason we often arrange to arrive before the seller has driven it). Cold start should be quick, smooth, no smoke from the exhaust. White smoke that clears within 30 seconds is normal on a cold morning. White smoke that persists is a head-gasket warning. Blue smoke is oil being burnt (worn rings or valve seals). Black smoke is a fuel-mixture issue.

25. Drive cycle including a freeway run

A 15 to 20 minute drive over a mix of suburban streets and at least a kilometre of freeway speed. We feel for transmission shift quality (clean and prompt is healthy, hesitation or harsh shifts is a warning), drivetrain noise at speed, engine smoothness through the rev range, and acceleration behaviour under load.

26. Brake feel under hard stop

In a safe place (an empty side street, not a main road), one hard brake application from about 50 km/h. The car should stop straight, without pulling, without pulsing through the pedal, without any noises. ABS should not activate on a dry road from this speed.

27. Turning and parking behaviour

Slow speed full-lock turning in both directions. A clicking or knocking noise on full lock is usually a CV joint issue (front-wheel-drive cars). Heavy steering, especially in one direction, is a power-steering or alignment issue. A bumpy steering feel when going over a small bump under turn is often a worn strut top mount.

28. Final visual under brakes and after the road test

After the road test, the car parks back at the seller's address. We do a final under-the-bonnet check for any fluids that have appeared on the engine that were not there before (a fresh oil leak that only happens with the engine fully warm), and a quick scan for codes that may have triggered during the drive.

Red flags that usually mean walking away

Some findings are negotiable. Worn brake pads are a $249 fix and a $249 deduction from the asking price, simple. Other findings are warning shots:

• Coolant in the oil or oil in the coolant. Head gasket. Major engine work. Walk away unless the car is priced at a heavy discount and you have planned for a rebuild.
• Excessive blue exhaust smoke under acceleration. Worn piston rings or valve stem seals. Major engine work in the near future.
• Transmission slipping or harsh shifts under load. Transmission work is the most expensive single repair on most cars ($3,500 to $8,000 on automatics).
• Structural rust at any chassis or suspension mounting point.
• Mismatched VIN tags or evidence of VIN tampering. Stolen-and-rebirthed cars are a real thing. We cross-check VIN tags at multiple locations and report any discrepancies.
• A history of multiple airbag deployments showing in the airbag module.

Across the pre-purchase inspections we have done in South East Queensland, we routinely find issues that turn into either a renegotiated price or an avoided repair bill. Hidden chassis damage on towed utes, hairline radiator and head-gasket leaks, transmission slip masked at the dealership, electrical faults that would have surfaced a week after purchase — the patterns repeat. The inspection fee is the cheapest form of insurance on a five-figure purchase.

How to book

If you have a used car you are looking at, the process is:

1. Call us on 0451 159 954 or use the quote form with the make, model, year, asking price and the seller's location.
2. We confirm the cost (typically $229 to $279 depending on the vehicle).
3. We coordinate the time with you and the seller. We attend at the seller's address.
4. The inspection takes 90 minutes to two hours.
5. We text you the headline result as soon as we are finished.
6. The written report with photos lands in your email within four hours.

Most inspections are booked within two to four days. If you have an urgent buy (another buyer interested, dealer pressuring you), tell us, we will often fit you in faster.

Full pricing and what is included is on the pre-purchase inspection service page. For typical brake and cooling-system costs you might be using in the renegotiation, the pricing page has every starting price in one place.

The bottom line

A pre-purchase inspection is the cheapest insurance you will buy this year on a used car. Two hundred-and-something dollars to know what you are actually buying, with a written report that gives you negotiating leverage or a clean exit. The math works almost every time.

If you are looking at a used car this week, book one before you put the deposit down. We will tell you straight what we find, and you will decide what to do with that information.