This is the full review. Mechanical systems, safety components, body condition, signs of past damage, and a road test. If you only want the mechanical systems assessed and do not need a body or cosmetic review, that is a different and narrower service, and we explain the difference further down this page.

Below is the actual checklist we work through on every mobile pre purchase inspection. Most shops will not publish one, which makes it difficult to compare what you are getting. Here is ours.

Engine and under-hood

We check for oil leaks at the valve cover, oil pan, and front and rear main seals. We look at coolant condition and level, and inspect the radiator, hoses and cap for pressure loss. Belts are checked for cracking and glazing. We inspect the air filter, which is a reliable indicator of how the previous owner treated maintenance generally. We look for evidence of recent cleaning around the engine bay, because a spotless engine on a high-mileage car often means someone wanted a leak to be harder to see.

Transmission and drivetrain

We check fluid condition where the vehicle allows it, and assess shift quality during the road test. On front-wheel-drive and all-wheel-drive cars we inspect the CV boots for splitting and grease loss, which is one of the most commonly missed items on a used car. We listen for driveline noise and check the differential and transfer case for leaks.

Brakes

We measure remaining pad material and rotor thickness against the manufacturer specification rather than judging by eye. We inspect the calipers, slide pins and flexible hoses, and check brake fluid condition. Worn brakes are not a reason to walk away from a car, but they are a concrete item you can raise with the seller.

Suspension and steering

We check ball joints, tie rod ends, control arm bushings, sway bar links and strut mounts for play, with the weight off the wheels. This matters, because a loaded joint hides its own wear and cannot be assessed properly from the driver’s seat. We inspect shocks and struts for leakage and look at the mounts.

Tires and wheels

We record tread depth on all four corners and read the wear pattern. Uneven wear tells you about alignment, suspension condition and sometimes about accident damage. We check the date codes, because tires older than roughly six years are due for replacement regardless of tread. We inspect the wheels for bends and cracks, which is a common finding in this region.

Body and past damage

We look for panel gaps that do not match side to side, paint thickness variation, overspray in door jambs and engine bay, mismatched fasteners, and repair evidence on the frame rails and inner structure. This section is what separates a full pre purchase inspection from a narrower assessment.

Electrical and interior

We test lights, wipers, horn, windows, locks, climate control and the infotainment system. We check that warning lights illuminate at key-on and extinguish correctly, because a bulb removed from the instrument cluster is an old trick that still appears.

Diagnostic scan

We read stored and pending fault codes, along with readiness monitors. Readiness monitors are the useful part. If they show as not ready, the vehicle’s computer was recently reset, which means fault codes may have been cleared shortly before you arrived to look at the car.

Road test

Every mobile pre purchase inspection includes a road test. We drive the vehicle. Cold start behavior, acceleration, shift quality, braking, steering feel, tracking, and noise at speed. A great many faults only appear under load, and a car that sits still during an inspection has not really been inspected.