Best Spark Plugs

Although some drivers may not be aware, spark plugs are one of the most vital auto parts. Spark plug health translates to better overall performance and fuel efficiency, increasing the service life of your car. It is important, therefore, that spark plugs are regularly checked to help avoid unwanted or costly repairs.

In this article, we recommend several of the best spark plugs of various brands based on value, longevity, and more to provide you with the right fit for your vehicle. Before purchasing new spark plugs, remember to consult your vehicle’s owner’s manual for specifications on which ones fit your engine and safe replacement practices.

Before replacing your spark plug, it’s important to purchase the proper replacement. The two things to note are spark plug material and temperature range. Try to match these features with the spark plugs that come standard with your vehicle. This information should be found in your owner’s manual.

Spark plugs play a vital role in the combustion process of your vehicle’s engine, and the difference between the right and wrong replacement engine spark plug can have a substantial impact on your vehicle’s lifespan. 

Types Of Spark Plugs

There are five general types of spark plugs:

• Copper
• Iridium
• Single platinum
• Double platinum
• Silver

Not only do the materials contribute to its performance, but so does plug design and fit within the engine.

The cheapest option of the five, copper, is known as the standard spark plug. These plugs have a copper centrode plated with a nickel alloy. Although relatively inexpensive, copper spark plugs are less durable than those made with other materials and need to be replaced more often.

Iridium spark plugs last longer than copper ones and require less energy to generate the spark that powers the engine. Single platinum plugs are nearly identical to copper plugs in build except for their platinum core, which provides them a much greater lifespan. Both of these options are more expensive than copper spark plugs.

Double platinum spark plugs have both platinum-lined center and ground electrodes. This makes them ideal for vehicles with wasted spark ignition systems.

The last option, silver, is weaker than iridium and platinum plugs and is generally reserved for older, high-performance vehicles.

Temperature Range

All spark plugs have a temperature range that represents the ability to disperse heat. “Hot” spark plugs transfer heat slowly. This reduces carbon buildup and can increase spark plug longevity. “Cold” spark plugs transfer heat quickly, and are suitable for performance vehicles with fast engines. Your owner’s manual should indicate the ideal spark plug heat range for your car’s engine.

Every brand of spark plug has a different place where heat range is indicated, but most can be found in the part number, with lower numbers meaning a colder plug while higher numbers indicating a hotter plug. For example, the NGK Iridium IX spark plugs have the part number “LFR5AIX-11.” Here, the “5” refers to the temperature range. Because these numbers are different across brands, it can be difficult to compare temperature ranges.

Most manufacturers recommend replacing your vehicle’s spark plugs every 30,000.0 miles. However, modern iridium spark plugs can last up to 100,000.0 miles and longer. It is best to check your owner’s manual for the specific make and model of the spark plug it has to determine its lifespan.

Telltale signs of bad spark plugs include:

• Regular engine misfires
• Reduced fuel economy
• Reduced engine pickup
• The engine produces loud noises while idling

Do Good Spark Plugs Add Horsepower?

A set of high-quality spark plugs may and a marginal amount of increased horsepower, somewhere between one and three percent. If anything, the right spark plugs can help keep your car at peak performance. 

How Much Does It Cost To Replace Spark Plugs?

The cost of replacing a set is typically very inexpensive. Individual spark plugs can range from $5 to $10. Other spark plugs made from more durable materials may cost around $20, but replacing a set should cost well under $100.

1. Best Value: NGK 7090 G-Power Platinum
2. Best for Hot Engines: NGK Iridium IX
3. Best Longevity: Denso #5304 Iridium Power
4. Best Stability: HiVehicle New Iridium
5. Best Premium Option: ACDelco OEM 41-962

Best Value

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What makes the NGK 7090 G-Power Platinum spark plugs stand out is the quality of their materials and their unbeatable price tag. The 7090’s platinum-tipped center electrodes produce better conduction for starts, while its copper cores aid in heat removal for better thermal conductivity. And we can’t overlook the pure alumina silicate ceramic insulator, which provides unmatched strength and heat resistance that give NGK spark plugs a reliable reputation. And at $20, it is hard for a lot of the competition to keep up.

Key Features

• Cost: Around $20
• Fine wire platinum-tipped center electrode
• Pure alumina silicate ceramic insulator
• Trapezoid-cut ground electrode
• Trivalent metal plating
• Corrugated ribs
• Copper core
• Triple-sealed

What Customers Are Saying

Amazon Review Score: 4.7 out of 5 based on over 3,800 reviews

Many reviewers claim that the NGK 7090 plugs are inexpensive and easy to install. The few negative reviews cite shipping misorders but no issues with the plugs themselves. 

Best For Hot Engines

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If you’re searching for optimum performance for your vehicle, look no further than the NGK Iridium IX spark plugs. Although they are more expensive than other spark plugs, their longevity and ease of use are tough to beat, especially in hot engines.

One of the key features of the plug is its high melting point, making the plug more suitable for engines that are generally in a greater heat range than most vehicles. Other notable features include a fine iridium tip and trivalent metal plating, both of which contribute to better fuel economy, superior corrosion resistance, and a consistently stable spark for better starts. 

Key Features

• Cost: Around $40
• High-grade alumina silicate ceramic
• 98 percent pure copper core
• Tapered-cut ground electrode
• Fine iridium tip
• Trivalent metal plating

What Customers Are Saying

Amazon Review Score: 4.7 out of 5 based on over 2,100 reviews

One complaint is that some customers needed to have the gap adjusted slightly on their plugs to make them fit their vehicles, yet many of these reviews were still ranked at 4.5 stars or above.

Best Longevity

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The Denso #5304 Iridium Power spark plug is great for improving the firing performance of your engine. It is one of the best iridium spark plugs on the market. The only real con is the price, which is higher than most of its competitors, but these plugs are built to last.

This plug’s tapered-cut U-groove ground electrode increases ignitability and decreases quenching. Its five-rib insulator also helps prevent flashover, and the copper-glass seal bonds the electrode and insulator to provide a gas-tight seal. The quality of all of these materials is also high, so don’t worry about these spark plugs breaking down quickly.

Key Features

• Cost: Around $30
• 0.4-mm iridium-tipped laser-wired fine wire center electrode
• Tapered-cut U-groove ground electrode
• Purified alumina powder insulator
• Five rib insulator
• Copper-glass seal

What Customers Are Saying

Amazon Review Score: 4.7 out of 5 based on over 500 reviews

Many reviewers note increased engine performance and better gas mileage after installing the Denso iridium plugs. Some of the top reviews also highlight the product’s longevity with some reporting these plugs last over five years. Negative reviews complain that the Denso spark plugs do not fit their engine. These can serve as a gentle reminder that new spark plugs should be the same, if not similar, model as what your vehicle was originally equipped with.

Best Stability

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HiVehicle New Iridium spark plugs are great for drivers who want high durability and a consistently stable spark. The 99-percent copper-clad electrode makes the plug great for conductivity, reducing the risk of false starts and breaking while working. HiVehicle also claims that its plugs improve fuel efficiency and emissions, as well.

One drawback to these spark plugs is that they are only compatible with select car brands: Chevrolet, GMC, Cadillac, Buick, Hummer, Oldsmobile, and Pontiac, making these spark plugs a limited option for other car owners.

Key Features

• Cost: Around $35
• 0.6mm laser-welded fine platinum tip
• Full automatic isopressing
• Trivalent metal plating
• 99-percent copper-clad electrodes

What Customers Are Saying

Amazon Review Score: 4.5 out of 5 based on around 500 reviews

Many positive reviews come from owners of the car brands advertised and they confirm these spark plugs’ compatibility. They also commend the unbelievable performance of these plugs, especially their smoothness and stability. Negative reviews are scarce, with one review citing poorer engine performance after replacing the spark plugs.

Best Premium Option

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AC Delco has been producing parts for General Motors for over a hundred years, and this dedication to quality is demonstrated by its ACD-OEM 41-962 spark plugs. Included in this listing is a set of Herlux spark plug wires, which help conduct power from the spark plugs. Although this brings the price of the package up, including these wires helps reduce the cost of buying them separately.

Notable specifications include a one-piece suppressor that creates a gas-tight seal great for reducing radio frequency and engine interference, as well as a pure copper core built for maximum fouling resistance.

Key Features

• Cost: Around $80
• Pure copper core
• Double platinum point pad
• Nickel and chrome alloy electrodes
• Includes 90-day warranty

What Customers Are Saying

Amazon Review Score: 4.7 out of 5 based on over 1,500 reviews

Many reviews commend the ease of installation of these plugs, with good remarks about the reliability of the spark plug wires, as well. There are a few negative reviews of this product, including some that say the plugs didn’t match their engine.

Spark plugs provide a small electrical spark that ignites fuel inside the combustion chamber. This then pushes the cylinder down and moves the car forward – making spark plugs a necessary part of your vehicle. The biggest issue our team of experts found that customers had was purchasing improper spark plugs that won’t work for their vehicles.

We cannot stress how important it is to take five minutes to read your owner’s manual to ensure you purchase a suitable replacement. Double-checking which type of spark plug you need for your vehicle will ultimately save you time and money, whether you choose the NGK 7090 or the ACDelco 41-962.

*Data accurate at time of publication.