On the part itself
Many original parts carry their OE number: printed on a label, stamped or engraved into the part, or moulded into plastic. Clean the part and look at every side, since the number can be on a face that is hidden while the part is fitted.
A part can carry several numbers, and not every one is the OE number. The part maker's own number, a casting or mould number and a production code can stand beside it or in its place. A casting number can belong to the raw casting, which several finished parts share.
The part in the vehicle is not always the original one. An earlier repair may have fitted an aftermarket part, which carries its supplier's own number and may or may not show an OE number as well, or a part with a newer or an older number than the one the vehicle was built with.
Take a photograph of the label or the marking before the part is cleaned further or sent away. A worn or dirty number is easy to misread, and a single wrong character can lead to a different part.
An example from the catalogue
One row of a vehicle’s parts list, as the vehicle’s page shows it.
| Vehicle | Volkswagen Passat 5 (3C) 1.6 (BSE, BSF, 75 kW) |
|---|---|
| Part | Oil Cooler, engine oil |
| OE numbers | |
| Aftermarket part numbers |
|
From the vehicle manufacturer
The vehicle manufacturer's parts catalogue lists the parts of its vehicles; what it covers differs between manufacturers. The parts department of a dealer of the make can usually search it with your vehicle identification number, tell you the OE number of the part you need, and check whether a newer number has replaced the one on your part.
This is the way to try when the part is missing or its number cannot be read. The answer depends on the vehicle and the part being identified correctly, so say exactly which part you mean and where on the vehicle it sits.
Paperwork can also give the number. An invoice from a dealer or a workshop often lists the OE numbers of the parts that were fitted, and the packaging of a genuine part usually carries its number.
Through the vehicle on this site
Our vehicle catalogue leads from the make to the model series and to the vehicle with its engine. The page of a vehicle lists its parts by name, and beside each part the OE numbers and the aftermarket part numbers. A search field above the list filters it by part name or number.
Choose the vehicle by its engine code, power, production period and the other details shown, not by its name alone: a model series often has several vehicles of one name.
These lists come from the catalogues of aftermarket suppliers, whose vehicles we match to the vehicles of our catalogue. An aftermarket part is listed for a vehicle when its supplier lists it for a vehicle of its own catalogue that we match to that vehicle of ours. Some of these matches are inferred, and the OE numbers beside the part are that supplier's cross-references. Neither proves that every OE number in the row fits your vehicle, and a part no supplier we collect offers for the vehicle is not in the list at all.
Through a part number you already have
If you have the number of an aftermarket part, for example from the part that is fitted or from an invoice, type it into the search on this site. The search covers aftermarket part numbers as well as OE numbers and part names. Where our catalogue holds that part, it shows the OE numbers its supplier lists.
If you know what the part is called, the part catalogue shows, for each part type, the OE numbers found in the supplier data we hold. Those lists are long, so narrow them down through the vehicle first where you can.
Check the number you found
- Compare it with a second source: the part against a catalogue, or a catalogue against a dealer of the make.
- Read it character by character. A letter O and a zero, or a letter I and a one, are different characters.
- Sources can show spaces and punctuation differently. Compare every letter and digit in order, including any letters at the end, and confirm the part before ordering.
- If the number on your part and the number a dealer names differ, ask whether one has replaced the other before ordering.