How to find the right used part for your car

1. Start with your registration

Your registration tells us the make, model, year, engine size and fuel type. On Vehicle Part Finder, add your reg and we only show parts listed as fitting your car. Find a part by reg.

2. Match the part number

The surest check is the part number on your old part. It's usually stamped or printed on a label: on the back of a headlight, on the housing of a starter motor or alternator, on the casing of an ECU. Ask the seller for the number on theirs, or for a clear photo of the label.

Numbers can be the car maker's own (often called the OE or OEM number) or the supplier's (Bosch, Valeo, Hella and so on). Either is fine as long as both of you are looking at the same kind.

3. Know your engine and gearbox codes

Engines and gearboxes are identified by a code, not just a size: one maker can have several different 1.6 diesels in the same year. The engine code is usually on the engine block or on a sticker on the cam cover, and sometimes on the service book. Your VIN (on the V5C logbook, at the bottom of the windscreen and on the door pillar) lets a dealer or breaker look up the exact build.

4. Check the details that change

• Facelift or pre-facelift: lights, bumpers and grilles often change shape at a facelift.
• Body style: a hatchback tailgate won't fit the estate; three-door and five-door front doors differ.
• Side: nearside is the left, offside is the right (which side is which).
• Colour code: for painted panels, the paint code is on a sticker in the door shut or under the bonnet.
• Options: headlights with LED or xenon, mirrors with heating or folding, seats with heating or airbags.

5. Look at sister cars

Many cars share parts with others from the same group: a Seat, Skoda, Audi or Volkswagen can share an engine, gearbox or electrics, and some Peugeots, Citroëns, Toyotas and Fiats were built together. That widens the choice of breakers who might have your part. See which cars share parts.