How to Check Out a Used Car Before Buying It

Buying a used car is a serious step that requires careful preparation and a competent approach. After all, its further operation, repair costs and overall reliability depend on how thoroughly you check a used car. The inCarDoc team has prepared for you a complete guide on how to check a used car before buying — from the search stage to the final check before purchase.

Where to start: preparing to buy a used car

Before you start looking at adverts, be clear on a few important points for yourself:

• Purchase budget (considering possible investments in repairs and registration)

• Desired car makes and models

• Priority requirements: body type, engine, transmission, fuel consumption, safety, availability of specific options

• Understanding what to look for when buying a used car — or simply asking yourself, "what should I look for when buying a used car?" — will help you stay focused and avoid emotional or rushed decisions.

Once you have determined these parameters, move on to the next stage — finding a car.

Finding a car: How to find the right one

You should look for it on trusted platforms: official dealers, well-known online platforms, or through recommendations from friends and acquaintances. Don’t chase low prices blindly — very cheap offers can hide serious problems. Use filters to search by key criteria and save the most promising options for further analysis. At this stage, it's also worth thinking about how to check used car listings properly to avoid wasting time on potentially risky vehicles.

When choosing immediately, pay attention to:

• Year of manufacture and mileage

• Number of owners

• Service history

• History of accidents and repairs

• Documents: original PTS (if there is a duplicate — reason to be wary).

And remember, to properly inspect a used car, you need to take into account both visual condition and technical serviceability.

Document verification: the first step to a confident purchase

Before you start inspecting a car, it is essential to begin with the most fundamental step — checking your documents. This is the basis of the whole deal and the first filter that helps eliminate dubious offers. One of the most important used car checks is to ask the seller to provide the full package of documents: vehicle passport, registration certificate, service book (if available), diagnostic card with the results of the last technical inspection, and insurance policies. All these papers must be original, without signs of forgery, erasures, or damage.

When thinking about how to check a used car before buying, pay special attention to the PTS. It contains crucial information such as the number of previous owners, the date of the first registration, customs clearance details (if imported), and the VIN-code. Cross-check the VIN-code with the one stamped on the car body — it should match exactly, letter by letter, digit by digit. This code is typically located on a metal plate under the bonnet, on the door pillar, or near the windscreen. Any inconsistencies between the documents and the actual car are serious red flags that may point to hidden theft, replaced plates, or other legal issues.

Another key part of what to look for in a used car is the service book. If maintained, it can reveal how regularly the car was serviced and whether the owner treated the car responsibly. It should document visits to service stations, mileage, oil changes, and any major repairs. Consistency in entries and logical mileage progression are vital. Discrepancies may indicate odometer tampering or neglected maintenance.

The diagnostic card is also important: it confirms that the car has passed inspection and is authorized for use. Verify that it's valid and wasn’t obtained through a “formal” shortcut. Insurance documents can reveal additional information — for instance, a policy issued recently and for a short term might indicate a rushed sale.

Finally, when buying a car from a private seller, we strongly recommend ordering a VIN report using online services. This step is one of the smartest used car checks you can do. It can provide a history of registrations, accidents, insurance claims, theft reports, liens, and outstanding loans. This background checks not only protect you from purchasing a problematic vehicle but also gives you solid ground to negotiate a fair price if any issues are found.

Body inspection: What to check for

A visual inspection of the body is one of the most important steps if you want to know what to check when buying a used car. The car should be clean, parked on a level surface, and examined in good lighting to ensure an accurate assessment of its condition.

Start by checking the colour of the body panels — any differences in shade might indicate that certain parts have been repainted, often a sign of previous repairs after an accident. Pay close attention to the alignment and evenness of panel gaps between the hood, doors, and fenders; uneven gaps may suggest poor-quality repairs or replaced parts.

Look carefully for signs of rust, particularly on the sills, wheel arches, and underbody. These areas are prone to corrosion, which could point to more serious structural issues over time. Also inspect for chips, cracks, and dents — not only on visible surfaces but also in less obvious places. Check the condition of the windows, headlights, and mirrors for any cracks or damage that might compromise safety or result in additional repair costs.

Examine the tires as well — the tread wear should be even across all tires. Uneven wear could be a red flag for alignment issues or suspension problems.

Don’t forget to inspect hidden areas such as beneath the rubber door seals, inside the wheel wells, and inside the boot. Serious damage or poorly done repairs are often concealed in these spots. All of these checks are crucial parts of understanding what to look for when buying a used car.

Interior inspection: wear and tear and general condition

The interior of a car can tell you a lot about its actual mileage and how carefully it was used. It’s an important part of any buying used car checklist.

Check it before you buy:

• Condition of the seats (especially the driver's seat), door upholstery, headlining
• Wear on the steering wheel, gear knob and pedals
• Functionality of windows, mirrors, seat adjustment
• All switches and controls: air conditioner, heater, window heater, radio or media system.
• Presence of extraneous odours in the passenger compartment (mould, dampness).

Always switch on the ignition and check the indicators on the dashboard. They should light up and go out as normal.

Electronics diagnostics: how to detect hidden problems

Checking the electronic systems is a crucial part of a thorough used car check before buying. Ensuring that all key components are functioning correctly can help you avoid hidden issues and make a more confident purchase decision.

Begin by testing all exterior and interior lighting — headlights, brake lights, turn signals, and dashboard illumination should work properly without flickering or delays. Make sure the onboard computer is operational and that there are no warning lights or error messages on the instrument panel, as even minor alerts may indicate deeper problems.

To enhance your inspection, consider using a mobile app like inCarDoc along with an OBD2 scanner. This setup allows you to run a basic diagnostic check: read any stored error codes, monitor the performance of key sensors, and access data about fuel consumption and engine operating modes. These insights provide valuable information about the vehicle’s electronic health and are an essential part of a proper used car.

Technical check: engine, transmission, suspension

To properly understand how to inspect a used car, pay special attention to the condition of the main units:

Engine

Check:

• No oil leaks, coolant leakage
• Cleanliness of the engine compartment
• Exhaust colour and odour
• Stability of idling
• Presence of extraneous noises

Be sure to open the oil filler neck: emulsion on the cap is a sign of issues with the cooling system.

Transmission

Mechanics and automatic:

• Ease of gear engagement
• No grinding or thumping
• Smoothness of shifting
• No jerks or jolts

Suspension

Check:

• No knocks or squeaks when driving over bumps
• Condition of shock absorbers
• Symmetry of ground clearance

It is also important to check the brakes: the pedal should be firm and the braking should be smooth with no sideways drifting.

Test drive: How to take a test drive

The test drive is a critical stage in understanding how to test drive and check a used car. It gives you the opportunity to assess the car’s real-world performance and identify any issues that may not be visible during a static inspection.

Pay close attention to how easily the engine starts — hesitation or unusual noises at startup can be early warning signs. Evaluate the gearbox operation: gear changes should be smooth and responsive, without grinding or delays. The steering should feel accurate, with good feedback and no excessive play. Listen carefully for any unusual noises when accelerating, braking, or driving over bumps — rattles, clunks, or whining sounds may indicate mechanical wear or suspension issues.

Observe how the vehicle behaves under acceleration and braking. It should gain speed smoothly and brake evenly, without pulling to one side. During the test drive, don’t hesitate to try different driving conditions — urban traffic, higher-speed roads, and maneuvering in tighter spaces — to get a full picture of the car’s handling and comfort. All these aspects are essential when learning how to test drive and check a used car effectively.

Final check and decision-making

After a thorough car inspection and test drive, it is advisable to draw up a car buying checklist. This will help you not to miss important details:

• Checking the VIN number
• Car history check
• Body and interior inspection
• Electronics check
• Engine and transmission diagnostics
• Suspension and brakes assessment
• Test drive results

If in doubt, ask a professional car mechanic or service centre for a full diagnostic.

Useful tips from inCarDoc

For a successful used car purchase, follow our used car purchase checklist:

• Prepare in advance: study the models and their weaknesses
• Don't rush into a purchase
• Don't be afraid to ask the seller uncomfortable questions.
• Be ready to walk away from the deal if you have doubts
• Use the inCarDoc mobile app for on-site diagnostics.

Buying a used car is always a risk, but a competent approach, knowledge of things to look at when buying a used car and thorough inspection can minimise it.

To support your evaluation on the spot, use the inCarDoc mobile app in combination with an OBD2 scanner. This setup allows you to read fault codes, monitor the performance of essential sensors, check fuel consumption, and evaluate the engine’s health — all directly from your smartphone. It's a smart, accessible way to boost your inspection with real diagnostic data.

There is always some danger involved in purchasing a used car, but you can lower the risk considerably by being well-prepared, exercising caution, and knowing what to look for. You can make a much more informed and secure purchase.

Download the inCarDoc app and have your car check.