Over the past 18 months I’ve inspected more than a hundred used cars before purchase, my own, friends’, clients’. Two things I learned for certain. First: you’ll catch 80% of the traps in half an hour with the naked eye, no lift, no €100 mechanic visit. Second: people lose thousands not because they don’t know cars, but because they don’t know what to check, in what order.

This article is the order. Step by step, from documents to test drive.

Before you drive out: online checks

The best-spent time in the whole process. From the listing alone you can filter out 30-40% of cars without leaving home.

1. Database history

You search by registration number and (if you have it) VIN. What you want:

Vehicle history check (MOT history at gov.uk/check-mot-history, equivalent national database), mileage from inspections, previous owners, registration dates.
Manufacturer recalls, some models had factory faults, the manufacturer replaced parts for free. If the car wasn’t recalled, you may have unresolved structural issues (e.g. BMW N47 timing chain).
Stolen vehicle databases, national + Interpol.
US salvage auctions (Copart, IAAI), if the car was sold there as “totaled”, it’s there in black and white with a damage map.

In MotoPPI all of this runs automatically when you paste a listing link. Manually, government MOT site + Google search (“VIN [number] copart”), takes 10 minutes.

2. Price vs market

AutoTrader / Otomoto / mobile.de show median price for the model, year, and mileage. Check your car:

20%+ below the median, almost always hides something. Salvage, rolled-back odometer, mis-registered import.
5-15% below, best deals. Seller wants out fast (divorce, debt, moving).
Above the median, dealer, broker, certified pre-owned.

Rule: if a car priced at €13k is going for €15k in the market, suspicious. Nobody undercuts €2k out of the goodness of their heart.

3. Reading the listing between the lines

Red flags in the description:

“Imported” without a specific country, often means a US salvage auction.
“Mint condition” + short generic description = listing written quickly, seller doesn’t want questions.
“Highly recommended” in the listing body = filler, seller has nothing else to say.
No VIN in the listing, deliberate.
Only distance photos, sharp angles, hiding something (rust, dents, paintwork).

On-site: 60 minutes of inspection

Once at the car, plan 90 minutes minimum, including the test drive, a full inspection takes 90 minutes.

Step 1: documents (5 minutes, before walking around the car)

Before you touch the car, sit down with the seller and check:

Registration document (V5C / equivalent), compare the VIN on the document with the VIN on the chassis (you’ll verify on the car later).
Service book, is there one, are entries dated, who serviced? No book on a “main dealer car” = signal.
Insurance/MOT validity, when does it expire. If next month, you have a negotiation lever.
Repair invoices, a seller with invoices has skin in the game. No invoices for a claimed “engine rebuild a year ago” = lie.

Step 2: paintwork (10 minutes)

The most often-lying area. What you do:

a) Look at the car from 3-5 metres away, at an angle. Original paint has a consistent shade from every angle. Shade differences between adjacent panels = repainted.

b) Use a paint thickness gauge if you have one. Standards:

80-150 μm, factory paint.
150-250 μm, minor repair (scratch, stone chip).
250-500 μm, proper repaint (collision).
500+ μm, body filler after a crash.

Measure 10-15 points per panel. A single reading tells you nothing.

c) Check the panel gaps between bonnet, doors, boot. They should be even and tight (3-5 mm). Inconsistent width = post-crash reassembly.

d) Look at the hinge bolts on bonnet and doors. Fresh wrench marks = someone unbolted them. Bonnet replaced or straightened.

Step 3: VIN plates (3 minutes)

This is how you catch “stitched cars”, two cars welded into one.

The VIN is in three places (check all):

Engine bay, on the firewall (between engine and cabin), stamped into metal.
Under the passenger seat, sticker.
B-pillar, open passenger door, on the frame.

All three must be identical and the same font. If any looks different, has welding marks, glue residue, or fuzzy digits, donor car parts.

Also compare against the registration document VIN.

Step 4: engine bay (10 minutes)

Open the bonnet. The car must be cold, engine cold to the touch. Otherwise the seller started it earlier to mask startup problems.

What you look for:

Fresh oil leaks, wet patches on the valve cover, around the oil filter housing seal. Sign of gaskets needing replacement.
Corroded parts in the bay that shouldn’t be (brake master cylinder, brake lines, expansion tank).
Welding marks or fresh paint on bare metal in the bay, post-crash repair.
Manufacturer plate, compare with the VIN. No peeling, no fresh rivets, no crooked font.
Fluids:
- Oil (dipstick), light amber = fresh, dark brown = old, whitish emulsion = water in oil (head gasket, oil cooler).
- Coolant (reservoir), oily rainbow film = oil cooler leaking.
- Brake fluid, low level = pads worn OR leak.

Step 5: undercarriage (10 minutes)

Bend down, phone torch on, look under the entire perimeter.

Fresh welds on floor, sills, wheel arches, post-crash repair.
Fresh paint in unusual places (e.g. a strip of floor under the rear seat).
Corroded sills, feel along the inside with your finger, under the plastic trim.
Fluid leaks, under engine, under transmission. Wet patch = active problem.
Suspension, control arm bushings cracked? Anti-roll bar links worn?
Brakes, discs. Lip (rounded outer edge) = disc nearly worn.

Step 6: interior (10 minutes)

Get in, look closely.

Rollback detection:

Steering wheel, leather at 9 o’clock and 3 o’clock. Worn smooth and shiny at 80k km = not true.
Gear knob (manual), worn shift pattern = high mileage.
Rubber pedals, wear from shoe contact. Throttle pedal especially. Fresh pedals + low mileage = OK. Fresh pedals + 250k km = replaced “for sale”.
Driver’s seat, worn cushion, outer bolster on door side. After 200k km it must show.

Rest of the interior:

A/C, turn on, does it cool quickly. “Recently broke” = condenser damaged in front impact.
All dashboard warning lights, none should stay on after startup.
All electric windows, indicators, wipers, heated seats, test one by one.
iDrive / infotainment, everything works? Module replacement is €350-700.

Step 7: cold start (5 minutes)

The most important 5 minutes. The car must be genuinely cold (engine cold to touch).

Turn on ignition, don’t start, watch the dash. Airbag light must come on for 4-7 seconds and go off. If it never lights up = airbags deployed, light disabled.
Start the engine. Listen to the cranking, long cranking = weak battery or fuel system issues.
Watch the exhaust pipe:
- Thick white smoke = head gasket.
- Blue/grey smoke = engine burning oil (rings, valve guides).
- Black smoke = mixture problem (lambda sensor, EGR).
Listen to the engine, smooth idle = OK. Short rattle 1-2 seconds on diesel start = chain tensioner at its limit.

Step 8: test drive (20 minutes)

You can’t finish an inspection without a test drive. Some faults only show up under load.

What to test on the route:

Motorway, car tracks straight without holding the wheel. Pulls to one side = geometry, suspension, or post-collision.
Hard braking from 80 km/h to zero, pedal vibration = discs need replacing. Car should track straight under braking.
Over bumps, knocks from front = control arms, anti-roll bar links. Knocks from rear = shocks, rear arms.
Acceleration under load (3rd gear, full throttle from 2000 rpm), jerking, power loss = fuel pump, turbo, sensors.
Manual gears, every gear under load. Pops out of gear = synchros worn.
Auto transmission, smooth shifts. Jerking = mechatronic.
A/C on motorway, actually cools? Or only when stationary?

Step 9: final conversation (5 minutes)

You’re back at the car, sitting with the seller. They usually want to know what you found.

Speak concretely:

“Three things don’t add up. One: valve cover gasket leaking, €180 repair. Two: brake discs have a lip, replacement €280. Three: suspension knocking over bumps, control arms €350. Total €800 in repairs. The price I’d offer: [X].”

This isn’t aggressive. This is concrete numbers the seller can’t argue with. They either agree or look for a buyer who doesn’t inspect.

What you DON’T need to do

Traps that beginners fall into:

Driving the car onto a lift at a mechanic. That’s €140 and 80% of things you see with a phone torch under the car.
Doing a 200 km motorway test drive. 20 minutes is enough. Most faults show up in the first 10 minutes.
Checking every dashboard light from the model manual. Focus on 5-6 typical faults for that specific model (check the model’s owner forum).
Negotiating “just €1k less” without justification. Without specifics the seller dismisses you. Every euro of negotiation needs a repair to justify it.

FAQ

Can I inspect a car without a paint thickness gauge?

Yes, but you’ll catch 60% of a full inspection’s value. You can judge paint visually (shade differences, panel gaps, hinge bolts). A gauge catches subtle repaints invisible to the naked eye. If you don’t plan to inspect more cars, rent for a day (€10-15 at tool rental shops). If you’ll check more often, buy one for €60-80, full tools list here.

How long should a car inspection take?

90 minutes excluding the drive. If the seller rushes you (“I have to leave in 30 minutes”), that’s a signal something’s hidden. An honest seller gives you the time you need.

Should I buy a car with no VIN in the listing?

You can ask for the VIN in a message before visiting. If the seller refuses to give the VIN pre-visit = end of conversation. Every honest seller shares the VIN immediately, because they have nothing to hide.

What if the seller won’t budge on price?

Three scenarios:

Car worth the asking price, you buy. Your inspection confirmed no hidden problems.
Car worth less, seller firm, you walk. You’ll find another in the same year and mileage within a week.
Car has faults, seller confident, seller knows other buyers are queuing. You walk too.

Never buy a car because “I can’t be bothered looking more”. The next one comes up within a week.

How do I detect a rolled-back odometer?

Four signs without OBD:

Steering wheel/seat/pedal wear inconsistent with mileage.
No service book entries.
Database history (national MOT records, manufacturer service history) shows higher mileage.
Brake disc and tyre condition doesn’t match the claim.

The more of these four, the more certain the rollback.

What’s next

Inspector tool kit under €120, what specifically to buy.
US salvage auction car, is it worth it, how to spot an American “totaled” car.
How to start earning as a car inspector, if you want to do this for others.

Download MotoPPI on the App Store, 30-point checklist with the app guiding you step by step. First check is free.