When it’s time to replace your spark plugs, you’re faced with the option of getting OEM or aftermarket replacement spark plugs. Which option is the right fit for you? That’s what this guide is for.
We’ll explore all the important factors to consider while shopping for replacement spark plugs. And then we'll talk about how OEM and aftermarket spark plugs compare to each other.
OEM and Aftermarket Defined
Before comparing both parts, let’s talk about what each one means.
- OEM parts are parts produced by either the vehicle's manufacturer or the company that produces parts for them. OEM stands for “original equipment manufacturer”.
- Aftermarket parts are parts produced by a third-party company. Aftermarket parts come in their own designs that differ from that of their OEM counterparts.
Now, let’s talk about the 4 most important factors to consider while looking for replacement spark plugs.
The quality of the materials and components is a large factor that determines how long a spark plug will last and how well it will perform.
OEM spark plugs are always consistent in terms of quality. When you buy OEM spark plugs, you know you’re getting the exact same ones that came with your car.
Aftermarket spark plugs vary widely in quality, but they’re usually made with lower grade materials. They’re also commonly produced with poor workmanship. Aftermarket manufacturers tend to do the bare minimum during the manufacturing and testing processes.
Aftermarket parts manufacturers often cut corners on spark plugs by:
- Installing lower quality ceramic insulators. These make the spark plug more fragile and increasing its likelihood of failing
- Leaving out the nickel plating on the plug threads, which often causes the spark plug to seize when it’s time to replace it
- Using nickel alloy coated tips, which reduces the plug’s lifespan
The above reasons are why quality matters a lot when it comes to spark plugs. OEM spark plugs certainly come out on top when it comes to quality.
Here’s a cool fact: spark plugs create enough electrical noise to interfere with the rest of your car’s electrical system. For example, it can interfere with the:
- Navigation system
- Sensor in the engine and exhaust system
That’s why all spark plugs come with an interference suppression resistor. The resisitor is a component that serves as a barrier between the electrical noise and the rest of the electrical system.
Many aftermarket manufacturers put substandard resistors in their spark plugs to keep costs down. If you put one of these spark plugs into your Nissan, you’ll likely encounter a variety of issues with your electrical system. With OEM spark plugs in your engine, you’ll have the peace of mind that they won’t interfere with the rest of your car’s electrical system.
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A spark plug is quite a finicky part. It has to be an exact length in order to maximize the engine’s power and fuel economy. A spark plug that’s just a little bit longer or shorter can reduce your engine’s power and increase its fuel consumption.
Many aftermarket spark plugs are built with universal fitment. An aftermarket spark plug could be the perfect size for one car, too long in the next car, and too short in a third car.
You might have better luck with an OE-quality aftermarket spark plug, but they’re not always built perfectly. If you want a spark plug with perfect dimensions, OEM is the way to go.
4. Electrode Design and Shape
The electrodes in the spark plug are designed a certain way to optimize engine performance and fuel economy. If they’re ground into a certain shape and designed with a certain gap, then your engine will get as much horsepower and mileage as it can. Nissan spent tons of time and money figuring out the best specs for the electrodes in its OEM spark plugs.
Aftermarket spark plugs rarely have the right electrode design and shape. This means that your engine performance and fuel efficiency won’t be optimized with aftermarket spark plugs in your engine.
Which Option is the Right Fit?
Whether you’re looking for optimal performance, maximized fuel economy, cost savings, or all of the above, OEM is the better option.
At NissanPartsPlus.com, we offer wholesale pricing for genuine OEM Nissan spark plugs. Look up your Nissan model here to see if we have spark plugs for your car.