Know what you’re buying
Is a history check enough before you buy a used car?
A reassuring history check is a useful starting point when you’ve found a car you like. Before you decide to buy, it’s also worth looking at its service paperwork, seeing the car and arranging an independent inspection. This guide explains how those checks fit together and what to ask the seller.
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What can a history check tell you?
A history check can bring problems to your attention that you might not spot in an advert. For example, HPI checks for outstanding finance, theft and insurance write-offs . These checks look for records of money still owed under a finance agreement, a car reported stolen, or damage that led an insurer to decide the car could not be repaired safely or economically.
Before choosing a check, have a look at what it includes. When you receive the results, make sure the car’s details match and read any warnings or checks that could not be completed. The report reflects the records available at the time; it cannot tell you about every repair or everything about the car’s condition today.
If information is missing, that part of the check remains unverified. It does not mean the car is clear of the issue being checked.
CarDiligence is independent of HPI and RAC. Each service has its own checks and terms. This guide helps you work out which questions you still need answered before buying.
Does an HPI check include service history or a mechanical inspection?
HPI’s answers to common questions explain that its history check does not include service records or an examination of the car’s mechanical condition. Its accident information covers damage recorded as an insurance write-off, so it is not a record of every accident.
History-check services can also help with price and running costs. HPI offers an estimated value where available, and RAC’s Full Check includes average running costs and an estimate of the cost of buying and running the car . These features are worth comparing with CarDiligence when deciding what would help you most.
We checked these descriptions on 20 September 2026. Features can change, so have a look at the provider’s current information before ordering.
An MOT is useful too, but it does not cover the condition of the engine, clutch or gearbox . An independent inspection can help you understand the car’s condition now, alongside its past test results.
Four questions to help you decide
| Your question | What to look at | What to do next |
|---|---|---|
| Know what you’re buying: do the details match? | The car’s registration, history results and mileages recorded at MOT tests. | Compare the car with its original documents when you visit. Ask about anything that does not match or could not be checked. |
| Know what you’re buying: has it been looked after? | Service records, invoices listing the work done and the manufacturer’s recommended servicing. | Ask for paperwork showing any major work mentioned in the advert. An independent inspection can help you check its condition. |
| Know what you’re paying: is the price reasonable? | Adverts for similar cars, estimated values and any problems found during an inspection. | Allow for differences in mileage, equipment and condition. Remember that an advertised price may differ from what a buyer eventually pays. |
| Know what it could cost you: does it fit your budget? | Garage quotes for work the car needs, estimated servicing and repair costs, and your own running costs. | Keep estimates separate from bills you know you will need to pay. Check whether a garage quote and an estimate include the same work before adding them together. |
The service-history guide helps you check the paperwork; the first-year budget guide explains which costs to allow for.
An example: the seller says the work was done, but the invoice is missing
A made-up example: an advert says “full service history and timing belt recently changed”. The timing belt helps keep the engine’s moving parts working together. The history check finds no issues in the checks it could complete, but the service book does not mention a new belt.
- What you know so far
- The history results look reassuring, but they do not confirm whether the timing belt was changed.
- What still needs checking
- Whether the seller has an invoice or another record of that work.
- What you could ask
- “Do you have an invoice for the belt change showing the car’s details, date and mileage? Could I see it at the viewing?”
- If the paperwork is missing
- A dealer or specialist can help you find the servicing requirements for that exact engine. Ask what they would recommend checking, and whether any work might be needed, before you decide to buy.
The work may have been done even if the invoice is missing. Missing paperwork alone cannot tell you whether the belt needs replacing. It gives you a question to follow up with the seller or a garage.
How can CarDiligence help?
CarDiligence brings together the vehicle records it can find and explains what they mean for your purchase. Where the information is available, your report compares servicing with the manufacturer’s recommendations, puts the asking price in context and gives you an estimated servicing and repair budget. It also suggests questions for the seller and things to check at the viewing.
Read how to get a report for a car you’ve found and what the report checks.
The information available varies from car to car. Service records may be incomplete, and sometimes we cannot find the manufacturer’s guidance, enough similar adverts or a cost estimate. If we cannot verify something, we say so; we never treat missing information as a clear result.
Our salvage checks look for records of damaged cars offered for sale. They do not replace a full check for insurance write-offs or stolen vehicles. When comparing reports, look at the individual checks included so you can see what you may still need.
You’ll still need to see the car and consider an independent inspection: our report does not include an inspection or a warranty. Any servicing and repair budget is an estimate to help you plan. It is not a garage quote and cannot predict whether a particular part will fail.
AI explains the checked evidence. It doesn’t invent the vehicle facts.
See what you could learn from a report . The sample is free to read and uses example information. If you’d like a report for the car you’re considering, you can order one using the advert link or enter the details yourself.
Before you pay for the car
- Check that the registration and vehicle identification number (VIN, the car’s unique identifying number) match the original documents.
- Read the history results, including anything that could not be checked. Ask for an explanation if something is unclear.
- Compare the service paperwork with the manufacturer’s recommendations for that car. Note any records you would like to see.
- Arrange a viewing, test drive and independent inspection. If the inspection finds work that needs doing, ask a garage for a quote.
- Think about the price and your budget with what you’ve learned in mind. Take time to get answers to the questions that matter to you before paying.
The official used-car buying guidance and our buying checklist can help you work through these steps. Together, the records, paperwork and inspection give you a fuller picture of the car you’re considering.