What Is a Manufacturer Part Number?

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What Is a Manufacturer Part Number?

When doing an automotive repair or scheduled maintenance, it is essential to buy the correct part that will fit your vehicle. To ensure this happens, it is helpful to use the manufacturer part number, or MPN. The MPN is the number assigned to the part by the manufacturer. Buyers can use the MPN to ensure they have the right part for their vehicle and that it is the same or equivalent to what is already on the car, and that it is the exact part they are looking for. 

Definition of a Manufacturer Part Number

A manufacturer part number is a series of numbers and/or letters that has been given to a part by the manufacturer. An MPN identifies the part as belonging to and originating from that one manufacturer. Each part the manufacturer makes has a different MPN. If two parts come from different manufacturers, they will have different MPNs. This allows businesses to identify which company made the part. For instance, a serpentine belt has different MPNs depending on who made it. The table below shows a few of the many MPNs for serpentine belts and the corresponding manufacturer.









Manufacturers may give a set of only numbers to their parts or a combination of letters and numbers, but each MPN is unique. Some buyers prefer to only buy from a certain manufacturer because of a reputation or because that manufacturer specializes in parts for a certain make of car. For instance, Bando is used on 80 percent of the top cars in the U.S., and anyone seeking a Bando product can research the MPN for the product they want and make sure that the product they purchase has the same MPN.

MPNs Vs. Part and SKU Numbers

Vendors may assign a different number to an auto part to record it in their own inventory, but this is different from the manufacturer-given number. Vendors' numbers are often called the "part number" or "SKU," and these numbers are based on whatever record keeping program they use. For instance, ABC company makes a certain headlight with the manufacturer part number 121212. ABC sells this headlight to a retail auto parts store, XYZ company. When XYZ lists the headlight in its inventory, it gives the part the number of 343434 because it is the next available number in their record-keeping system. The manufacturer part number or MPN is the number that ABC gives the headlight because it is the company that actually made it, but the part number from XYZ is what is used to locate the headlight in the store.

Types of Manufacturer Part Numbers

There are generally two types of parts when it comes to auto products: OEM and non-OEM parts, also known as "aftermarket parts." This designation is unique to the auto industry, and it can be important to know the difference when searching by MPN.

OEM Parts

OEM refers to the original equipment manufacturer, and an OEM part is identical to the original part that was placed on the vehicle at the time of assembly. OEMs can be thought of as the various car makes out there – Ford, Honda, Cadillac, Nissan, etc.

Car companies assemble the whole vehicle using thousands of parts from a wide-range of third-party suppliers of specialized parts, as well as parts that they manufacture themselves in house. All of these parts will have an OEM part number associated with them (whether made by the OEM or a third-party) and will be labeled with the name of the OEM car manufacturer. 

Non-OEM Parts

Non-OEM parts are compatible with OEM parts and can be used in place of OEM parts on an automobile. However, they are not made by the same manufacturer as the original parts and are often compatible with more than one make of car. Generally, non-OEM parts are more "generic" or "universal." For instance, buyers may find a part that works for multiple cars from General Motors. These may be termed "meets OEM standards" to specify that they follow the same specifications. Another name for non-OEM parts is aftermarket parts..

With new cars, the buyer generally only has the option to purchase an OEM part to replace an original part on the car. The manufacturer of a new car (OEM) purchases exclusive rights for the parts from its parts suppliers and the suppliers agree to sell only to the car manufacturer. After the car is a couple years old, the parts suppliers have the right to make the same parts and sell to other wholesalers as well as put their own label on it instead of the label of the car manufacturer. These are considered non-OEM parts, and they are often less expensive than OEM parts sold by a dealer. Additionally, certain aftermarket parts companies will design copycat parts to attempt to be the same specifications as the OEM parts, but these will have that company's label on them.

Choosing the Right Part

Because non-OEM parts are deemed aftermarket parts and may fit different makes or models of cars, they are often less expensive than OEM parts. The non-OEM parts may not carry the same warranty as OEM parts, but are designed to fit the car. Most repair shops use aftermarket parts on cars two years and older unless the owner requests only to use OEM parts. If buyers know the MPN, they can use it to find a replacement non-OEM part online that works the same as the OEM part and costs less.

How to Identify a Manufacturer Part Number

To find the manufacturer part number, buyers can visit the manufacturer's website or they can ask the customer service person at an auto parts store for the name of the manufacturer and the MPN. The OEM company representatives generally identify MPNs for a particular car using a diagram of the part assembly. Some companies will have these diagrams available on their websites and you can determine the MPN yourself. You can also use that to determine the correct name of the part if you want to look for equivalent aftermarket parts. Each manufacturer part number is unique and may have a combination of letters and numbers, but the style varies by manufacturer. 

How to Buy Car Parts Using MPNs

Buyers can find car parts at any physical auto parts store by asking for a specific manufacturer or giving the MPN. The salesperson can look up the item by manufacturer and find the SKU number, which indicates where the part is located in the store. Buyers can also find these parts online by searching MPNs. If shoppers search online by manufacturer, they can locate many online sellers of those exact car parts.

How to Buy Car Parts on eBay

When buyers want to search on eBay for car parts, they can enter the manufacturer part number into the Search field that appears on any eBay page, if they know what the MPN is. Buyers can also enter the MPN and the manufacturer (brand) name or item name to narrow the results even further. For instance, buyers could enter "5061025 serpentine belt" or "5061025 Dayco belt" into the Search field, and eBay will return the exact item queried.

If buyers find an item listing that does not specify the MPN, but they think it is the correct part, they can contact the seller and confirm the part number before making a purchase.

Choosing the Right Seller

Since car parts can be quite expensive, buyers want to make sure they are working with a reliable seller. Once they find the correct item, they can research the sellers who have that item to find one who meets their requirements. Some sellers offer free shipping, or buyers may be able to sort results for local sellers so they can pick up their item and save on shipping costs. Buyers can check out the sellers' ratings and feedback scores to ensure that other buyers have not had problems or customer service issues in the past with this seller.


Buying car parts by MPN ensures buyers that they are getting the exact same part as what is currently on their car or the exact part they want for their car. Different manufacturers label their parts in different ways, and other numbers can be added by vendors, such as SKU numbers. Buyers can also choose between OEM and non-OEM ("aftermarket") parts for their vehicle and use the manufacturer part number to guarantee they are getting the correct item. It is easy to find items by MPN on eBay and other online and physical locations to make it easy to get the right part to fit any automobile.

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