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Volkswagen Replacement Spark Plugs: OEM or Aftermarket?

Choosing between OEM parts and aftermarket parts can be overwhelming. There are so many factors to take into consideration. OEM is usually the better choice, but it’s especially the case when it comes to spark plugs.

Why it Really Matters Who Makes Your Replacement Spark Plugs

VW Spark PlugImage Credit: Paul79UF

Spark plugs are such important components of your engine. The risks of installing cheap or generic replacement spark plugs far outweigh the sole benefit, which is cost.

To save money, many aftermarket manufacturers:

  • Use lower grade materials.
  • Do the bare minimum during manufacturing and testing.

While quality is an important factor in all car parts, it’s a really important factor in spark plugs.

The Dangers of Using Cheap Spark Plugs

The most common ways an aftermarket parts manufacturer cuts corners on spark plugs are:

  • Omitting nickel plating on the plug threads. This often causes the spark plug to seize when it’s ready to be replaced.
  • Using either just platinum or low grade iridium platinum alloy coated tips. This cuts down the plug’s lifespan.
  • Installing low quality ceramic insulators. This makes the spark plug more fragile and more likely to fail.

The bottom line: cheap spark plugs cause a lot of problems. The risks associated with cheap spark plugs are high enough that it’s not worth saving a few bucks on them.

Even High-Quality Aftermarket Spark Plugs Aren’t That Reliable

Even with aftermarket spark plugs built with high-quality materials, the rule is still caveat emptor. These aftermarket spark plugs may be made with the right materials, but that doesn’t mean they’ll function as well as they’re expected to. Aftermarket spark plugs need to be made to the exact same specifications as OEM spark plugs. The following factors really matter:

  • Size: OEM Volkswagen spark plugs come in a very specific size. They’re a certain length and their electrode gap is a certain size to optimize the engine’s power and fuel economy. Many aftermarket manufacturers give their spark plugs a generic, one-size-fits-all design. This helps to broaden their customer base. There are some OE-quality aftermarket spark plugs available for purchase. But chances are these spark plugs don’t have the exact same dimensions as OEM spark plugs. Even if the size is slightly off, your engine’s power and fuel economy will still suffer.
  • Interference suppression: Spark plugs create electrical noise that can interfere with the rest of the electrical system. That’s why every spark plug is built with an interference suppression resistor. Many aftermarket spark plugs come with a low-quality suppression resistor that doesn’t do its job. This increases the risk of interference affecting your Volkswagen’s electrical system. You may experience problems with your radio, navigation system, or even sensors in the engine or exhaust system.
  • Electrode shape: Volkswagen carefully designed the spark plug electrodes to be a certain shape that optimizes performance and efficiency. Aftermarket spark plugs usually don’t sport the same shape, and that means decreased power and efficiency.

The Benefits of Using OEM Replacement Spark Plugs

OEM VW plugs

OEM spark plugs are a much better choice than aftermarket spark plugs for the following two reasons:

1. High Quality Materials

Determining the quality of aftermarket spark plugs is a gamble. There’s no way to know how well an aftermarket spark plug will hold up except to actually install it and use it yourself. With OEM spark plugs, you know the spark plugs you’re getting are designed specifically for your Volkswagen engine. And, they are sold by the same manufacturer that produced your car and all the parts in it.

Volkswagen OEM spark plugs are made with:

  • High purity platinum-iridium alloy coated tips.
  • Nickel-coated threads to fight corrosion.
  • High-grade ceramic insulators.

All of these materials ensure durability, longevity, and reliability.

2. Cost

We mentioned before that cost is a benefit of using aftermarket replacement spark plugs. We’re not trying to confuse you – we promise!

What we mean is that a lot of people think aftermarket spark plugs are cheaper than OEM spark plugs. It’s actually the other way around. OEM spark plugs may cost a little more upfront. But, they’re actually cheaper in the long run because:

  • They’re more durable.
  • All OEM spark plugs are protected under Volkswagen’s Parts and Accessories Warranty. It is good for one year or 12,000 miles, whichever occurs first. Many aftermarket manufacturers don’t even warranty their spark plugs.
  • You’ll get optimum fuel economy with OEM spark plugs because they’re built to provide the best performance for your engine. Aftermarket spark plugs actually decrease your car’s fuel economy, and the losses add up over time.

The Bottom Line

It’s okay to save a bit of money on certain types of car parts, if they don’t impact your VW’s performance or safety. Spark plugs definitely don’t fall in that category because they play such a vital role in the operation of the engine. If you value safety and reliability, OEM is the only way to go.