What is an OEM part number and how do you find it?

Two parts sold under the same name may not fit the same car. Search for "Golf 7 air filter" and you will find several different filters depending on the engine. The surest way to avoid the wrong part is to know its number.

What does OEM number mean?

The OEM number is the number the car manufacturer gives to a part. For example, the manufacturer number of a Volkswagen air filter looks like 5Q0 129 620 B. The companies that make the part (such as MANN, Bosch or TRW) also sell the same part under their own numbers; the list showing which of their numbers matches which OEM number is called a cross-reference.

At OTOREN, the OEM and manufacturer numbers of every product are shown on the product page. You can type the number into the search box with or without spaces; both work.

Where to find the number

1. On the old part. It is stamped on the housing of filters, on the backing plate of brake pads, on the hub of discs and on the label of shock absorbers. If it is covered in dirt or rust, wipe it and take a photo with your phone.
2. On the old part's box or invoice. If you have bought the same part before, the invoice and box are the quickest source.
3. With your VIN. Dealer workshops and parts specialists can see the car's exact specification from the VIN and find the right number. We explain where to find your VIN in the Where is the VIN (chassis number) and how do you read it? guide.
4. By selecting your vehicle. When you choose the make, model, year and engine, the site lists only the parts that fit your car.

Why might the number match but the part not fit?

• Production change: The same model may have changed a part in the middle of a model year. That is why the year and engine matter.
• Equipment differences: Versions with or without air conditioning, with sports suspension or with larger brakes use different parts.
• A previously replaced part: The old part on the car may itself have come from a different car. Checking with the VIN reduces this risk.

For products marked "No compatibility data · check required", always compare the number with your old part. Even for products marked "Fits your vehicle", checking the numbers once before fitting is a good habit.

FAQ

Is an OEM number the same as a genuine part?

The OEM number is the part's number. You can buy the part matching that number in a genuine box, under the OEM supplier's own brand or as an aftermarket part.

Can I find the part number with my VIN?

Yes. The VIN shows the car's production details, and parts specialists use it to find the right number.

This guide gives general information. Torque values, fluid quantities and service intervals vary by vehicle; follow your owner's manual. If you are unsure about safety-related work, ask a mechanic.