Key takeaway: Spending 10 minutes on checks before buying a used car can save you thousands. Here are the 10 most important things to look for, starting with free online checks that filter out problem cars before you even visit.
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1. MOT History
The MOT history is the most valuable free data point available. It reveals the car's mechanical condition over years, including every advisory, failure, and mileage reading since 2005.
What to look for:
- Recent advisories: These are future repair bills. CarCostCheck translates them into plain English with cost estimates.
- Recurring issues: The same problem appearing year after year suggests a fundamental fault.
- MOT failures: One or two failures over a long history are normal. Multiple failures in consecutive years suggest neglect.
- Structural advisories: Corrosion to structural elements is expensive to fix and a safety concern.
Run a free check and review the full MOT timeline before visiting the car.
2. Mileage Verification
Mileage clocking affects an estimated 2.3 million UK cars. CarCostCheck's free report analyses the mileage readings from every MOT test and flags inconsistencies. A sudden drop in mileage, or a year where the car barely moved, can indicate tampering.
Also check: does the physical wear (pedals, steering wheel, seat) match the claimed mileage? A car showing 25,000 miles should look nearly new inside.
3. Stolen, Finance, and Write-Off Status
These three checks protect you from the biggest financial risks:
- Stolen: Police can seize a stolen car. You lose everything.
- Finance: The finance company can repossess it. You lose everything.
- Write-off: A Cat N or Cat S write-off is not necessarily a deal-breaker, but you need to know about it to make an informed decision and negotiate the price.
CarCostCheck premium covers all three for £4.99.
4. V5C Logbook
The V5C (logbook) is the vehicle's registration document. Check:
- The seller's name and address match the V5C
- The VIN on the V5C matches the car's VIN (dashboard and door jamb)
- The document looks genuine (watermark, print quality)
- The document is the original, not a "new keeper" supplement
5. Running Cost Estimate
The purchase price is only part of the cost. CarCostCheck's free report estimates annual running costs including fuel, road tax, MOT, and predicted repairs. A car that is £1,000 cheaper to buy but £500 more expensive to run each year is not actually cheaper.
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6. Bodywork Inspection
Walk slowly around the car and look for:
- Mismatched paint colours between panels
- Orange peel texture or overspray (signs of repainting)
- Uneven panel gaps (suggests accident damage)
- Rust bubbles under the paint, especially around wheel arches and sills
- Filler under the paint (tap panels gently; filler sounds different to metal)
7. Tyre Condition
- Legal minimum tread is 1.6mm, but aim for 3mm+
- Uneven wear indicates alignment or suspension problems
- Check all four tyres and the spare
- Budget £50-150 per tyre for replacement
8. Test Drive
Drive for at least 15 minutes, covering different speeds and road types:
- Listen for unusual noises (knocking, grinding, whining)
- Check brakes from various speeds
- Drive over bumps to test suspension
- Test all gears including reverse
- Check for pulling to one side
9. Engine Bay
- Check oil level and condition on the dipstick
- Look for oil leaks (check the ground under the car)
- Check under the oil filler cap for creamy residue (head gasket issue)
- Check coolant level and colour
- Look for loose or damaged hoses and wires
10. Professional Inspection
For cars over £5,000, a professional pre-purchase inspection (£100-200) from the AA, RAC, or an independent mechanic is worthwhile. They use equipment and expertise that most buyers do not have, and can spot issues that would otherwise be missed.
Your Complete Toolkit
| Feature | CarCostCheck Free | CarCostCheck Premium £4.99 | Typical Paid Service £19.99 |
|---|---|---|---|
| Full MOT history (every test since 2005) | ✓ | ✓ | ✗ |
| MOT advisories in plain English | ✓ | ✓ | ✗ |
| Estimated repair costs per advisory | ✓ | ✓ | ✗ |
| Mileage verification / clocking detection | ✓ | ✓ | ✓ |
| Reliability score (0-100) | ✓ | ✓ | ✗ |
| Annual running costs breakdown | ✓ | ✓ | ✗ |
| Fuel cost calculator | ✓ | ✓ | ✗ |
| Insurance group estimation | ✓ | ✓ | ✗ |
| Red flag alerts | ✓ | ✓ | ✗ |
| Common faults for make/model | ✓ | ✓ | ✗ |
| Stolen check (PNC) | ✗ | ✓ | ✓ |
| Outstanding finance check | ✗ | ✓ | ✓ |
| Write-off check (Cat A/B/N/S) | ✗ | ✓ | ✓ |
| Previous keeper count | ✗ | ✓ | ✓ |
| VIN verification | ✗ | ✓ | ✓ |
| Colour change history | ✗ | ✓ | ✓ |
| Price | Free | £4.99 | £19.99 |
Frequently Asked Questions
What are the most important checks before buying a used car?
MOT history, mileage verification, stolen/finance/write-off status, V5C verification, running costs, bodywork, tyres, test drive, engine bay, and professional inspection for expensive cars. CarCostCheck covers the first five online.
How long should checking a car take?
Online checks take under a minute. Physical inspection takes 30-45 minutes. Test drive, 15-20 minutes. Budget about an hour total for the viewing.
What is the biggest mistake buyers make?
Not checking the car online before viewing. A free CarCostCheck report takes seconds and rules out problem cars before you waste time and money visiting.
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12 checks included. Free MOT analysis, mileage verification, running costs, and more. Premium stolen, finance, and write-off checks for just £4.99.
Related reading: Complete 2026 Buying Guide | How to Spot a Clocked Car | Do I Need an HPI Check?