Searching by OEM and Equivalent Part Numbers in Spare Parts Sales

When the phone rings at a company that sells spare parts, the caller rarely says, "I need a set of brake pads." The mechanic or dealer reads the number off the box in their hand, and sometimes sends a photo. In spare parts, the common language is not the product name but the part number. That is why, if the search box on your B2B portal does not understand part numbers correctly, every other feature takes a back seat.

In this article, we explain why searching by OEM and equivalent part numbers is difficult, how this search should be designed in a good system, and how you can prepare your data for it.

OEM, Genuine, Equivalent: Different Names for the Same Part

Let's start by clarifying the terms. In the industry, these terms are sometimes used interchangeably, and the confusion carries all the way into the order.

• OEM part number: The number the vehicle manufacturer assigns to the part. Most of the references dealers have are OEM numbers, because that is what appears in the service catalog and on the old part.
• Genuine part: A part sold under the vehicle manufacturer's logo, through the manufacturer's own channel.
• Manufacturer (brand) part number: The code in an aftermarket manufacturer's own catalog. A single OEM number can correspond to five different codes from five different manufacturers.
• Equivalent (aftermarket) part: A part made by another manufacturer with the same dimensions and function as the OEM part.
• Cross-reference: The mapping table that links these numbers together. It holds information like "This OEM number corresponds to these three products in our catalog."

Here is the problem: dealers search with whichever number they know. If a product in your system is recorded only under your own stock code, the dealer cannot find the part even when it is in stock, and reaches for the phone.

Part Number Normalization: Differences in Spaces, Hyphens, and Periods

The same number is written differently in different places. It may have spaces on the box, hyphens on the invoice, and no separators at all in the ERP. And dealers type the number however they happen to remember it. All of the following spellings, which we made up for illustration, actually point to the same part:

Normalization means stripping separators such as spaces, hyphens, periods, and slashes from a number before searching, and converting the letters to a single case (usually uppercase). Both the stored numbers and the text the dealer types go through the same rule, and the comparison is made on these clean versions. That way, "how it was written" stops mattering and "what was written" comes to the fore.

The benefits of normalization are not limited to the dealer side. The same rule applies when your sales team searches for a number read out over the phone, or when your warehouse team checks the number on a box. When everyone finds the same number with the same result, you eliminate lost sales caused by parts that were sitting on the shelf while someone said, "We don't have it."

Details to Watch Out For

• Leading zeros: In some manufacturers' numbers, a leading zero is meaningful; in others, it gets lost during an Excel import. The normalization rule needs to account for this.
• Mixing up O and 0, I and 1: This is common with handwritten numbers. Fully automatic correction is risky, but a "Did you mean this?" suggestion works well.
• Partial search: Dealers may remember only part of the number. It should be possible to search by a fragment that appears within the number.
• Revision suffixes: A letter at the end of the number sometimes indicates a new version of the part. Whether the old and new versions can replace each other should be defined separately.

Cross-Reference: Every Match in a Single Search

Normalization makes sure the number is read correctly; cross-referencing finds that number's matches. In a well-designed system, when a dealer types an OEM number, they should see the following results on a single screen:

1. The genuine product linked to that OEM number (if in stock),
2. Equivalent products that correspond to the same number, with the manufacturer's name and their own codes,
3. The dealer-specific price and stock status of each.

This structure matters from a sales perspective too. If the genuine product is out of stock, the dealer does not land on an empty results page; they see the equivalent option. The sale is not lost; it simply shifts to a different product. By seeing the price difference between the equivalent and the genuine part on the same screen, the dealer can also offer options to their own customer.

Cross-reference data is not a one-time job. The table needs to be updated as new products arrive and supplier codes change. That is why, in practice, being able to bulk-upload mappings via Excel and track who added which mapping is extremely useful.

Vehicle Fitment: A Second Path for Dealers Who Don't Know the Number

Not every dealer knows the number. Small repair shops and new staff in particular think in terms of "the front brake pads for this vehicle." This is where vehicle-based filtering comes in: as the make, model, year, and engine are selected, the list narrows down to only the parts that fit that vehicle.

If vehicle fitment is not designed correctly, it backfires. Different engine options for the same model, or changes within a production year, may require different parts. That is why fitment data should be kept as detailed as possible, and in uncertain cases the dealer should see a note such as "Confirm with the VIN." Shipping the wrong part means shipping costs, return costs, and a hit to the dealer's trust in you.

Preparing Your Data for Search

Even the best search infrastructure cannot deliver good results with poor data. Taking these steps before moving to a portal will make things easier:

• Separate the number fields: Do not put your own stock code, the OEM number, and the manufacturer number in the same field. Keep each in its own field.
• Support multiple OEM numbers: A single part can correspond to numbers from more than one vehicle manufacturer. Store them as a list instead of writing them comma-separated in a single field.
• Enrich your product information: Dimensions, images, and technical notes help dealers make sure they are choosing the right part. We covered the impact of product information on sales separately.
• Make sure your stock data is up to date: Even if search finds the right part, the dealer will still pick up the phone if the stock is wrong. On this topic, see our article What Happens When Stock Data Isn't Updated in Real Time.

Spare Parts Catalogs with Multistok B2B

Multistok B2B syncs two ways with your ERP to bring stock and price data into the portal, and your dealers place orders with their own prices and discounts. How the number fields, equivalent part mappings, and search behavior will be designed is decided together during setup, based on your existing data structure. For other automotive needs, see our automotive industry page and our article on what to look for in B2B software for automotive spare parts.

Conclusion

In spare parts, the search box is the hardest-working member of your sales team. A setup that reads a number regardless of how it is written, extends from the OEM number to equivalents, and offers vehicle-based filtering when needed reduces phone traffic, cuts down on wrong-part shipments, and keeps you from losing sales because a genuine part is out of stock. The foundation for all of this is well-maintained part number data.

If you would like to see how your own catalog would look on the portal, you can request a free demo.

Frequently Asked Questions

What Is the Difference Between an OEM Part Number and a Manufacturer Part Number?

The OEM part number is the code the vehicle manufacturer assigns to the part. The manufacturer part number is the code in the own catalog of the aftermarket company that produces that part. A single OEM number can correspond to more than one manufacturer number.

What Does Part Number Normalization Do?

It ignores separators such as spaces, hyphens, and periods, as well as differences in letter case, so that the search is based on the content of the number. That way, the dealer reaches the right product no matter how they type the number.

Where Do We Get Cross-Reference Data?

Common sources include supplier and manufacturer catalogs, your own sales history, and industry data providers. Whichever source you use, the data needs to be updated regularly.

Does the Vehicle Fitment Filter Always Give Accurate Results?

It depends on how detailed the data is. Since there can be differences within the same model depending on the engine and production period, showing a suggestion to confirm with the VIN in doubtful cases reduces the risk of the wrong part.