How do I find the part number for a car part?
The part number is stamped, etched or printed on the part itself — usually on a flat face, a moulded boss or a white label. Clean the area and photograph it. If the part is still on the car, the number can also be looked up from the vehicle registration or VIN, which resolves to the exact build specification.
- Look on a flat face, moulded boss or white sticker
- Clean off grease first — numbers are often legible underneath
- Photograph it rather than typing it out; digits are easy to misread
- OE numbers come from the manufacturer; aftermarket numbers do not cross over
- A registration or VIN resolves to the build spec if the part is unreadable
- Suffix letters matter — 06B 903 016 AB is not 06B 903 016 A
Most wrong-part returns are not caused by a dishonest seller. They are caused by a buyer describing the part by make and model, and a seller sending exactly what was asked for. The part number is the only thing in the whole transaction that is unambiguous, and finding it takes about two minutes.
What a part number actually is
It is the manufacturer’s own identifier for one specific component, at one specific revision. Two cars that look identical, built the same year, in the same trim, can carry different part numbers because of a mid-year supplier change, a market variation or an optional extra. Make and model narrows it down. The part number settles it.
Where to find it on the part
- Cast or moulded in — common on engine, gearbox and suspension castings. Look on flat faces and raised bosses.
- On a white or silver label — usual for electrical units, ECUs, alternators, starters and control modules.
- Etched or stamped — glass, lighting units and body panels often carry a small stamped block near an edge or a mounting point.
- Printed on the housing — plastic parts, ducts, trims and covers.
Grease and road dirt hide more part numbers than wear does. Wipe the area with a rag and degreaser before you decide the number is missing. Then photograph it — reading a number off a photo is far more reliable than copying it by hand, because 8/B, 0/O, 1/I and 5/S get confused constantly.
OE numbers versus aftermarket numbers
An OE number is the vehicle manufacturer’s own. An aftermarket manufacturer uses its own catalogue number, which will not match. Both are valid ways to identify a part, but they do not cross-reference automatically — so tell the seller which one you are quoting. If you have the OE number, lead with that.
Suffixes are not decoration
A trailing letter or two normally marks a revision. Sometimes revisions are backwards compatible and sometimes they are not, particularly on electronic modules where the software differs. Quote the number in full, including any spaces and letters, and let the supplier confirm whether an adjacent revision will fit.
If you cannot read the number at all
Send the vehicle registration or the VIN instead. A registration resolves to the build specification, which identifies most parts correctly. It is not quite as precise as a part number on a car that has had components swapped over its life, but it is far better than a model name. We accept either — send us the number, the registration or a photo and we will confirm the part before you pay.
Why this matters more on an export order
A wrong part on a UK repair is an annoyance. A wrong part that has already crossed an ocean inside a container is a write-off, because returning it costs more than the part is worth. That is why every unit on an export order should have its number recorded on the packing list and the commercial invoice — it is what identifies the item if there is any dispute later.
Frequently asked questions
Everything you need to know about buying, selling and shipping car parts with LJ Auto.
Where is the part number on a car part?
It is normally on the part itself — cast into a flat face or boss, printed on a white label, or stamped near a mounting point. Clean off grease first, because dirt hides more part numbers than wear does.
Can I find a part number from my registration?
Yes. A vehicle registration or VIN resolves to the build specification, which identifies most parts correctly. It is slightly less precise than the number on the part itself if components have been swapped during the vehicle's life.
Do aftermarket part numbers match OE numbers?
No. An aftermarket manufacturer uses its own catalogue number, which will not match the vehicle manufacturer's OE number. Tell the supplier which type you are quoting so they can cross-reference it correctly.
Does the letter on the end of a part number matter?
Usually yes. A trailing letter normally marks a revision, and revisions are not always interchangeable — especially on electronic modules where the software differs. Always quote the number in full.
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