Are OEM Honda Spark Plugs Worth It?

Honda OEM Spark Plugs

Your Honda’s spark plugs aren’t designed to last forever. When it comes time to replace them, you have two options:

1. Buy genuine OEM Honda spark plugs

2. Pick up whatever the corner auto parts store has in stock

Should you opt for the OEM quality plugs for your Honda, or go the less expensive route and get cheap aftermarket plugs? If you have the best interest of your engine in mind, it’s hard to argue against using OEM plugs over aftermarket replacements. Here’s why you need to reconsider using cheap aftermarket spark plugs in your Honda.

OEM Plug Anatomy

It’s hard to tell by just eyeballing an aftermarket plug that it’s different, and that’s what those manufactures are counting on — that you won’t know the difference. Where the quality division begins and ends is in the materials and specs of the components which make up a spark plug. Here’s how a standard OEM Honda plug is constructed:

Platinum or Iridium Center Electrode. A OEM Honda plug will have a platinum (90k mile rating) or iridium tip (120k mile rating). These are both costly metals, but prolong the life of your plug. One of the first corners cut by aftermarket brands is making plugs with a low grade center electrode.

High Quality Ceramic Insulator. The role of the insulator in the plug is to insulate the central electrode and terminal studs from the spark plug shell. If the quality is low, it can crack during installation, or later on when the temperature from the engine rises. The reason low quality insulators are used on aftermarket plugs is because they cost less for the manufacturer.

Nickel Plated Spark Plug Shell. The metal casing around the plug wheel protects the plug and secures the spark plug into the cylinder head of your Honda. High quality OEM plugs have a nickel-plated shell since this material is resistant to corrosion and won’t seize in the cylinder head. The coating on most aftermarket plugs is often quite thin and offers little protection against rust or the change of a plug seizing in the head.

Superior Interference Suppression Resistor. The spark plugs in your engine create a lot of electromagnetic signals as they fire — these signals have the potential of interfering with vehicle electronics. To keep this from happening an interference suppression resistor is used inside each spark plug to keep the signals from causing electronic noise which interferes with the function of various electronics.

Plugs with cheap interference suppression resistors can cause static in your speakers, possibly effect the function of your navigation system, and even cause issues with vital sensors like the ABS wheel speed sensors, crank position sense, and others. Cheap aftermarket plug makers are know for using low grade interference suppression resistors.

Exact Plug Body and Electrode Fitment and Dimensions. Engine tolerances are extremely tight and the spark plug must be a precise length to operate properly. Just a few hundredths of an inch too long and the plugs can interfere with the pistons or valves — a tiny bit too short and combustion will be incomplete. One way aftermarket plug manufacturers save expense is they make the plugs slightly too short to ensure they don’t damage engine components, but at the same time, they don’t have to manufacture with precision. OEM plugs are uniform in length, electrode size, shape, and gap for the best combustion efficiency.

Why You Should Care About OEM Plug Quality

You may be wondering why you would care about all the makeup of an OEM plug, and why it matters to you. Cheap plugs don’t last as long, but more importantly, all of this lack of efficiency is going to hit you at the pump first.

Say, for example, your aftermarket plugs don’t have have the mentioned high quality materials and are too short, your fuel economy is going to suffer. The decrease isn’t mind-blowing by any means, but it will add up. If your Honda gets 24mpg, and you drive 15k miles yearly, a 2% decrease in fuel economy will cost you $37.50 for those paying $3 a gallon for gasoline.

Add that up for 3 to 5 years and you’re wasting $100-$200 on fuel. Add that into the cost of your cheap plugs, and you’ve saved nothing — then you have to replace them far before the OEM plugs.

Conclusion on OEM Plugs

By using OEM quality plugs, you are helping your Honda’s engine run at its best. They may cost a little extra up front, but they are made precisely for your engine. Not only do they last longer, but they keep efficiency at its peak and save you hundreds at the pump.