It might be quite difficult to buy a new spare part for your own car – especially if you have not tried it previously. You can make it easier on yourself however by using a good dealer, and furthermore it is also important to understand the terms of OEM and IAM.

You can read more about these terms in this article, so be on your marks, if you want to be sure that the new spare part will fit your car.

The short version explaining the OEM number

OEM represents Original Equipment Manufacturer and is a term used for spare parts sold from the original manufacturer of a car. In other words, it goes for the spare parts you will find in new cars of a specific make. Occasionally only the short-term OE number is used.

It is a good idea to use original spare parts when repairing your car, as these spare parts are typically of high quality. You can use the OEM number of the defective part to find a replacement, because if the two spare parts have the same OEM number, you can be sure they fit your car.

Extended explanation of OEM, IAM and MPN

As previously mentioned, it is a jungle to get a grip on all the terms and concepts about spare parts. OEM is surely the most important term, but you may also meet terms as IAM and MPN.

The difference between OEM and IAM

OEM stands for Original Equipment Manufacturer, while IAM stands for Independent Aftermarket Manufacturer. In other words, OEMs are the original parts, while IAM are non-original parts from other manufacturers.

IAM spare parts also have an IAM number that you can use to identify a specific spare part. IAM spare parts are typically cheaper than OEM parts, but choosing non-original parts is not necessarily an advantage.

IAM spare parts can be problematic because they can come from bad manufacturers. On the other hand, the quality may be fine, but you get a quality guarantee when you choose an OEM spare part.

What does MPN mean?

MPN stands for Manufacturer Part Number and is the number used by manufacturers to identify their spare parts.

Like with OEM number, you can use MPN to identify a spare part. If the OEM number of a part matches the OEM number of the same part of your car, then the part will fit 100%

Want to save money on OEM spare parts?

New OEM parts are expensive because they are of high quality. It also means that they can last for a long time, so therefore they can be a good investment.

If you want to save money on your spare parts, you may choose to buy OEM spare parts. You must bear in mind that IAM parts may vary in quality, and consequently the OEM part is a good alternative.

When you buy used spare parts, it is a good idea to use a qualified dealer, for you to be sure that a thorough quality check of the used parts has been carried out. At the same time, it also guarantees, that you in fact get the spare part you paid for.

Use Autoparts24 when you want to buy used spare parts

By using Autoparts24 when you buy used spare parts, you are ensured an important guarantee of quality. All parts have been selected by professional car dismantlers, and the parts have been thoroughly controlled prior to being put up for sale.

When you purchase with Autoparts24, all you need to know is the OEM number or det original spare part number. By entering this number in the search, you will be shown at list of all relevant spare parts fitting your car.

It is a great advantage to choose used spare parts, as you will get the spare parts much cheaper than new parts, and you will receive a part, with only minor superficial wear. The superficial wear and tear of the item has no influence of its lifetime, as it will typically last longer than an IAM spare part.

FAQ on OEM number and spare parts

We would like to hep you if you have any questions about the OEM number, and consequently we have gathered a small list of answers to questions you may have.

What is an OEM number?

OEM represents “Original Manufacturer Number”. If the spare part is an OEM, it means that it is the exact same spare part you will find in brand new cars from the manufacturer of the make. In other words, it is a sign of quality which indicates that the spare part has been approved by the manufacturer and estimated to be the best choice for the car.

Where do I find the OEM number?

You will most often be able to find the OEM number on all spare parts of the vehicle. However – be aware that it might be difficult to see the number, if the spare part is dirty, and the number might even be hidden, if the spare part is still in mounted in the car.

If you want to use the OEM number of the spare part, the best is to dismount the part, to be sure to be able to read the number correctly, as this is the number you will need to buy a new part.

Where do I find the OEM number in my car?

The easiest way is to show you where to find the OEM number in your car, – however please be aware, that it may vary for each manufacturer. If you have any problems finding the number, you may also contact your mechanic or garage and ask for their help.

Below please see some examples of where to find the OEM number on a spare part.

Why is the OE number so important?

The OE number is important, as you use it to identify fitting spare parts for your car. If the OE number of your defective spare part corresponds exactly with the OE number of the new part, you are sure that the new part will also fit your car.

The OE number is also important, as it guarantees that the quality of the spare part is approved by the original manufacturer of the car.

Top guides

• Injection system in the car explained simply - parts and function of the injection...
• Maintenance and repair of electric cars: what can your normal garage do?
• Increasing performance with chip tuning: benefits, risks and tips
• Guide: Computer systems and software in your car
• Which electric car parts need repair or replacement most often?
• What is a solid-state battery for electric cars?
• All about engine sensors: from combustion engines to electric cars
• Increase the range of an electric car: How every electric car gets further
• Electric car battery life: How to extend the life of the battery
• What is the compression of a car engine?
• This is the cubic capacity of a car engine
• Internal combustion engine valves: function, defects and repair
• Core components of the internal combustion engine - parts and functions
• Engine lubrication in cars: components, function and defects
• The environmental impact of manufacturing new car parts
• All about pollutant classes and their role in environmental protection
• Engine overhaul: What is an engine overhaul and how much does it cost?
• OEM car parts manufacturing: the key components of the sector
• Understanding engine power - insight into the technology of the car engine
• The steering system of the car - structure and operation
• The car's braking system - structure, parts and function
• Engine types in the car: V-engine, in-line engine and boxer engine explained
• 8 tips before buying a used electric car
• Distinguish OEM parts, aftermarket and counterfeit car parts
• The EPC indicator light is on or flashing: What to do?
• Master brake cylinder: function, defect detection and repair
• OEM car parts for hybrid and electric cars
• Used youngtimer and classic car parts - the best tips
• Cruise control: Function and repair of the cruise control system in the car
• Exhaust system: Everything you need to know about parts and function of the exhaus...
• Locking system: security and reliable locking on the car
• The engine's air intake system - parts, function and replacement
• Brake caliper defective? How to replace it yourself
• Fuel system: parts of the fuel supply from the tank to the cylinder
• Air conditioning system: function and components of your car air conditioning syst...
• The clutch: structure and function explained simply
• Detecting and replacing a defective fuel pump
• Surprised? So many pumps work in your car
• The most common causes of a defective electric car
• The 6 most important safety components of your car
• Identify and repair a defective starter in a flash
• 5 common chassis problems and how to fix them
• 10 unknown car parts that many drivers do not know about
• Engine cooling: function and important components of the cooling system
• Differences between petrol and diesel engines
• All-wheel drive: How the mechanics and components of all-wheel drive work
• Engine control unit car: Everything about components and functioning
• Defective engine control unit: causes, symptoms and repair
• HP vs. torque: What is the difference between power and torque?
• EV motors basics: How are they built, how they work and differ from combustion eng...
• The chassis: overview and function of all suspension components
• Used electric car parts: What to look out for
• The importance of the chassis number when buying used car parts
• ABS pump defective? Function, repair and replacement
• Injection nozzle defective? Diagnosis, cleaning and changing the injection nozzles
• Alternator defective? What symptoms occur and when to change the component
• Water pump defective? Symptoms and how to repair or change it
• Steering gear defective? What are the symptoms and when should the component be re...
• Lambda sensor defective? What are the symptoms and can I clean the sensor?
• Defective air conditioning compressor - what are the symptoms and when should the ...
• Intake manifold defective? Replace gasket or clean manifold?
• Exhaust manifold leaking? Symptoms of a defective exhaust manifold or gasket and w...
• Turbocharger defective? Repair or change?
• Servo pump defective? What symptoms occur and when you should change the part
• Clutch broken? - These symptoms indicate a defect in the clutch
• Common problems and repair of defective drive shafts
• Causes of engine noise and what to do about it?
• What can car diagnostic devices do and do I need an OBD scanner?
• When and how to replace brake discs and brake pads
• Brake warning lamp lights up - causes and what to do?
• EGR valve defective: Avoid engine problems and clean EGR valve
• Improve fuel consumption: How your car uses less fuel
• Squeaking brakes: Why brakes squeak and how to get rid of it
• Safely jacking up a car: How to jack up a car using a jack and jack stands
• How a defect in the muffler becomes noticeable and how it is replaced
• E-car motor: These electric car parts you can replace yourself
• Engine overheated: What you should do if the engine overheats
• Engine check lamp lights up: What you should do as a motorist
• The engine code: What does the code mean and where can I find it on the car?
• Tools for car repair: These 10 tools you should own
• Car repair mistakes: These are the 7 most common car repair mistakes
• The gearbox code: What does the code mean and where can it be found on the gearbox...
• Used parts: How to check the quality of used car parts
• Vehicle transmission: What is the difference between manual and automatic transmis...
• Mileage: This is how mileage affects used spare parts
• Car recycling: What happens to the car when it is recycled? 
• OEM original parts or aftermarket: these are the differences 
• Advantages and disadvantages of new and used car parts
• Starting problems? Top 9 reasons why your car does not start
• What’s that smell from my car? Top causes and cures
• Advantages of shopping scrap car parts online vs. going to the local breaker yards...
• 10 most frequently purchased car parts from car breakers/junkyard
• Important car parts and their function
• Common car engine problems: Diagnosing, Troubleshooting and Fixes
• Best tips for setting up your own home car workshop
• 7 Car parts replacements and repair tasks you should not do yourself
• DIY Car Maintenance and Repair Tasks
• Guide: How to Maintain and Protect Your Car Engine
• Best practices for Engine Rebuild
• Common Causes of Rear Differential Noise, troubleshooting, and how fix it
• Common Causes of power steering noise and how fix it
• Your Guide to Car Engine Components and Functions
• Licence plate and VIN information
• Top 10 of the most popular brands in second-hand autoparts
• France is just so cool