OEM vs Aftermarket Car Parts: What’s the Difference?

When it comes time to replace a car part, you may come across terms such as OEM, genuine, original equipment and aftermarket. But what do these terms actually mean, and is an aftermarket car part a good alternative to an OEM part?

Understanding the difference can help you make a more informed decision when buying replacement car parts.

At Velocity Auto Spares, we specialise in aftermarket VW and BMW car parts, offering replacement components for a wide range of vehicles and applications.

What Does OEM Mean?

OEM stands for Original Equipment Manufacturer.

In the automotive industry, an OEM is a company that manufactures components for vehicle manufacturers or to the vehicle manufacturer's specifications. The terminology can sometimes be confusing because OEM, OE and genuine parts are often used interchangeably, even though they can refer to different supply and branding arrangements.

A genuine replacement part is generally sold under the vehicle manufacturer's brand and through its authorised parts network.

For example, a replacement component purchased through a vehicle manufacturer's dealership may carry the vehicle manufacturer's branding and packaging.

What Are Aftermarket Car Parts?

Aftermarket car parts are replacement components manufactured for vehicles by companies other than the vehicle manufacturer.

The aftermarket industry includes a very wide range of manufacturers and suppliers. This means aftermarket parts can differ considerably in terms of materials, manufacturing processes, specifications, quality and price.

The important thing to understand is that “aftermarket” describes where and how a replacement part is supplied, not automatically whether the part is good or bad.

When purchasing an aftermarket part, the manufacturer, specifications, application and correct fitment should all be considered.

OEM vs Aftermarket Parts: What Is the Difference?

There are several important differences to consider when comparing OEM and aftermarket car parts.

Feature	OEM / Genuine Parts	Aftermarket Parts
Manufacturer	Vehicle manufacturer or OE supplier	Independent parts manufacturer
Branding	Usually vehicle manufacturer branded	Usually manufacturer's own brand
Price	Generally more expensive	Often more affordable
Availability	Often available through dealerships	Available through many parts suppliers
Choice	Usually limited to the manufacturer's offering	Multiple manufacturers and options
Fitment	Designed for the specific vehicle application	Designed for specific vehicle applications
Quality	Factory/OE specification depending on part	Varies between manufacturers and products

These differences mean there isn't one answer that applies to every vehicle or every replacement part.

Are Aftermarket Car Parts Good?

One of the biggest misconceptions about aftermarket parts is that they are automatically inferior to OEM parts.

The reality is more complicated.

There are many aftermarket manufacturers producing replacement components for specific vehicle applications, but quality can vary significantly between manufacturers and products.

When buying an aftermarket car part, look at factors such as:

• Manufacturer reputation

• Correct vehicle application

• Part specifications

• Materials and construction

• Warranty

• Product quality

• Customer reviews where available

• Correct part number or cross-reference

A properly selected aftermarket replacement part can be a practical alternative to a genuine vehicle-branded component.

Why Are Aftermarket Parts Usually Cheaper?

One of the biggest reasons motorists consider aftermarket parts is price.

Genuine vehicle-branded parts are commonly sold through the manufacturer's distribution network and dealerships. The cost can include manufacturer branding, distribution, dealership overheads and other parts-network costs.

Aftermarket manufacturers operate independently and compete with other suppliers in the replacement-parts market.

This competition gives motorists more choice when looking for replacement components.

However, price should not be the only consideration.

An extremely cheap part from an unknown manufacturer may not offer the same level of quality as a reputable aftermarket component. Comparing the manufacturer, specifications and warranty is therefore important.

OEM vs Aftermarket: Which Parts Can Be Bought Aftermarket?

A large number of vehicle components are available from aftermarket manufacturers.

Common examples include:

Engine Mounts

Engine mounts support the engine and help isolate engine vibration from the vehicle.

Symptoms of worn engine mounts can include excessive vibration, knocking or movement from the engine during acceleration and unusual movement when changing gears.

Control Arms

Control arms form an important part of a vehicle's suspension system.

Worn control arms or associated bushes and ball joints can contribute to knocking noises, uneven tyre wear, steering problems and poor handling.

Wheel Bearings

Wheel bearings allow the wheels to rotate smoothly.

A worn wheel bearing can produce a humming, rumbling or grinding noise that changes with vehicle speed.

Cooling System Components

Radiator hoses, water flanges, thermostats and other cooling-system components are commonly available as aftermarket replacements.

A damaged cooling component can result in coolant leaks and, if ignored, potentially contribute to engine overheating.

Breather Hoses

Breather hoses are used in engine ventilation systems and can become brittle, cracked or damaged over time.

A damaged breather hose can contribute to air leaks and other engine-running issues depending on the vehicle and system design.

How Do I Choose the Correct Aftermarket Car Part?

Choosing the correct part is one of the most important steps when buying aftermarket car spares.

Simply matching the vehicle model isn't always enough.

For example, the same model may have different engines, transmissions, body styles or production years.

Before ordering a replacement part, check:

Make: Volkswagen, BMW, Audi, etc.

Model: Golf, Polo, 1 Series, 3 Series, etc.

Year: The production year can affect compatibility.

Engine: Different engines may use different components.

Engine code: Where available, the engine code can provide an additional level of accuracy.

Part number: Comparing the original part number or a recognised cross-reference can help confirm compatibility.

Vehicle specification: Certain components can differ depending on drivetrain, transmission, body style or production period.

If you're unsure about compatibility, providing your vehicle's registration or VIN to a parts specialist can also help with identification.

OEM vs Aftermarket: What Should You Consider?

Instead of looking only at whether a part is OEM or aftermarket, consider the complete picture.

Price

Aftermarket parts can provide additional options at different price points.

Availability

An aftermarket replacement may be easier to source than a vehicle-branded component, particularly for older vehicles.

Manufacturer

The manufacturer of an aftermarket component is an important consideration. Different aftermarket brands can have very different levels of quality.

Fitment

A part that isn't designed for your exact application can cause problems regardless of whether it is genuine or aftermarket.

Warranty

Check what warranty is offered with the replacement component and understand the supplier's terms.

Vehicle Age

For an older vehicle, an aftermarket replacement can be one of several options available when maintaining the car.

Genuine vs OEM vs Aftermarket: What's the Difference?

These terms can be confusing.

Genuine part: A part sold under the vehicle manufacturer's branding, generally through its authorised parts network.

OEM: Refers to the original equipment manufacturer. In automotive parts discussions, the term is often used to describe parts produced by an original equipment supplier, although terminology varies between suppliers and markets.

Aftermarket: A replacement component produced and sold by an independent manufacturer for the replacement-parts market.

Because these terms are sometimes used differently by different suppliers, it is worth checking exactly what is being offered rather than relying on the label alone.

Should You Buy OEM or Aftermarket Car Parts?

The right choice depends on the vehicle, component, manufacturer, budget and individual requirements.

Some vehicle owners prefer genuine parts and the manufacturer's branded replacement components. Others choose aftermarket parts because they want additional options in terms of price, availability or manufacturers.

If you choose aftermarket, focus on correct fitment and a reputable product, rather than assuming that every aftermarket component is the same.

The most important thing is to make sure the replacement part is suitable for your specific vehicle and application.

Buying Aftermarket Car Parts in South Africa

Finding the correct spare part can be difficult, especially when different versions of the same vehicle use different components.

Velocity Auto Spares supplies aftermarket car parts for a range of Volkswagen and BMW models in South Africa.

Our catalogue includes replacement components such as engine mounts, control arms, cooling-system components, breather hoses, wheel bearings and other automotive spares.

When searching for a replacement part, always check the listed vehicle compatibility and specifications before placing your order.

Velocity Auto Spares — doing it right, one part at a time.

Frequently Asked Questions

Are aftermarket car parts cheaper than OEM parts?

Aftermarket parts are often available at lower prices than vehicle-branded genuine parts, although the price varies depending on the manufacturer, component and supplier.

Are aftermarket parts reliable?

Reliability varies between manufacturers and products. Consider the manufacturer, specifications, warranty, construction and correct vehicle application when choosing an aftermarket part.

Do aftermarket parts fit the same as OEM parts?

Aftermarket parts are designed for specific vehicle applications, but correct fitment depends on the particular product. Always check the make, model, year, engine and other relevant specifications.

Is aftermarket the same as OEM?

No. OEM refers to the original equipment manufacturer, while aftermarket refers to replacement parts supplied by independent manufacturers for the replacement market.

How do I know which spare part fits my car?

Check your vehicle's make, model, year, engine and engine code where applicable. Comparing the original part number can also help confirm compatibility.

Final Thoughts

OEM and aftermarket car parts both have a place in the automotive replacement-parts market.

Rather than choosing a part based solely on the word OEM or aftermarket, look at the manufacturer, specifications, compatibility, warranty, availability and price.

For motorists looking for aftermarket VW and BMW spare parts ,as well as other brands, in South Africa, Velocity Auto Spares provides replacement components for a wide range of applications.

Always confirm compatibility before ordering and choose the part that meets the requirements of your vehicle.