Buying Guide
How To Read an OE Number and Match a Replacement Part
A practical method for reading the reference number on a used component and matching it to a replacement listing without guesswork.
Why the Number Matters More Than the Model Name
A vehicle model name is not precise enough to order a part. The same nameplate can run three different suspension packages, two air conditioning systems and several engine variants inside one production run, and a mid-cycle facelift will often change a bracket or a connector without changing the name on the boot lid.
The original equipment reference number is precise. It identifies one part, in one revision, for one set of applications. That is why every listing on this site leads with the reference numbers rather than a marketing description.
Where To Find the Number on the Old Part
On most components the number is cast, stamped, laser-etched or printed on a label. Clean the surface before you look. On an air suspension strut it is usually on the top mount plate or on a sticker around the air sleeve. On an air conditioning compressor it is on the body label next to the clutch. On a control arm it is cast into the arm itself. On an ignition coil it is printed on the body. On an oil filter housing it is cast into the aluminium.
Photograph the number rather than transcribing it. The characters O and 0, and I, 1 and l, are confused constantly, and a single wrong character sends the enquiry to the wrong part.
Reading the Structure of the Number
Different manufacturers use different structures. Mercedes-Benz numbers are usually ten digits, often written with spaces, such as 2213303303. BMW numbers are commonly eleven digits beginning with the group code, such as 11428507697. Volkswagen Group numbers combine an engine or platform code with a function code and a revision letter, such as 06E115405C, where the trailing letter is the revision. Land Rover numbers often start with LR followed by six digits.
The revision letter matters. A part ending in A and the same part ending in K may share a housing but differ in a sensor port or a mounting boss. Send the full number including any trailing letter.
Cross References and Superseded Numbers
Manufacturers supersede numbers. An early reference is replaced by a later one that fits the same applications, and both stay in circulation in the aftermarket for years. That is why many listings on this site show several numbers together: they are alternates for the same application, taken from our own catalogue records.
If your number does not appear on any page here, it does not automatically mean we cannot supply it. Send it to us and we will check it against the supersession chain.
The Four Things To Send With Any Enquiry
The reference number, or a clear photograph of it. The vehicle identification number, which resolves the build specification when a number is ambiguous. The quantity you need. The destination country, so freight can be quoted at the same time.
With those four pieces of information a quotation can normally be prepared the same working day.
More Guides
- How an Air Suspension System Works
- Signs an Air Strut or Compressor Is Failing
- Choosing the Right Air Conditioning Compressor
- Diagnosing Control Arm and Tie Rod Wear
- Ignition Coil Failure and How To Confirm It
- Water Pump and Thermostat Replacement Explained
- How To Buy Replacement Auto Parts From a Chinese Supplier
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FAQ
Questions About Buying Guide
What if the number on my part is unreadable
Photograph the whole part from three angles, include a ruler or a tape measure for scale, and send the VIN. In most cases the application can be resolved from the VIN and the photographs together.
Does an OE number mean the part is made by the vehicle manufacturer
No. Reference numbers are quoted for identification so that the correct application is clear. Unless a listing states otherwise, the number describes what the part fits, not who produced it.
Can you supply against an aftermarket brand number
Often, yes. Send the aftermarket number and we will try to resolve it back to the original equipment reference.
Next Step
Send the Reference and We Will Confirm It
Every enquiry is checked against the catalogue before a price is given.