Many car owners take the mighty spark plug for granted. It's a simple yet crucial device that's responsible for delivering the spark that ignites the fuel mixture in your engine. There's more to it than that, though. Your engine needs a spark plug that offers the right temperature, gap, and fit to ensure the best performance of your engine. Once you figure out those basic details, you need to find out what's the best spark plug within those parameters. That's the part we're here to help you sort out.
Best Spark Plugs Reviews & Recommendations 2021 BEST OVERALL NGK Iridium IX Spark Plugs+6 NGK 6619 Iridium IX Spark Plugs snagged the top pick in our spark plug comparison because they offered the best mix of high-performance, fuel efficiency, durability, and dependability. Featuring an iridium construction, these high-quality spark plugs provide a longer lifespan than copper and platinum spark plugs. Its ultra-fine electrode wire promises superior fuel efficiency as well as silky-smooth engine idle and response. You can also expect a healthy boost in power and torque, thanks to the optimal air-fuel mixture that these iridium spark plugs generate. It receives top marks for durability too, with such impressive features as metal plating to resist corrosion and seizing, as well as a long insulator nose to prevent fouling. BEST VALUE Denso Platinum Spark Plugs If you’re in the market for solid all-around spark plugs that are easy on your wallet, look no further than Denso 4504 PK20TT Platinum Spark Plugs. These value-priced platinum plugs pack a lot of performance, efficiency, and durability for a downright reasonable price. Featuring a dual-platinum construction, with a platinum disc and platinum electrode tip, these spark plugs provide a reliable spark to generate smooth, reliable combustion of the air-fuel mixture. This translates to great engine dependability, fuel efficiency, and performance. Another impressive feature is purified alumina powder, which is used as an insulator to increase thermal conductivity for maximum longevity. PREMIUM PICK Bosch Copper with Nickel Spark Plug To boost cold starts and enhance fuel ignition, these spark plugs feature a nickel chromium ground electrode. They have a heavy-duty yttrium enhanced copper core center for optimum performance, reliability, and heat transfer. These plugs are very durable and have a long lifespan. The nickel-plated shell provides anti-seize and corrosion protection. No gapping is required, and the plug's ribbed insulator prevents flashover. The plugs remedy misfires in certain vehicles, can increase mileage in some vehicles, and may boost performance by a noticeable amount. MOST DURABLE Bosch Copper with Nickel Spark Plug This OE replacement plug has a long lifespan and is very durable. The iridium firing pin is welded with a 360-degree continuous laser, and the copper core is designed to reduce fouling. The wire is ultra fine, and the nickel-plated shell prevents it from seizing. No gapping is required, and the plug has corrosion protection. One of the best things about these plugs is that they last a long time, which is important if you have an engine in which the plugs are difficult to access. While you may not notice a change in mileage when you install them, you may see a boost in performance. They are also very reliable, and you don't need a special gap tool for installation. HONORABLE MENTION NGK V-Power Spark Plug This spark plug includes a 90 degree V-Power center copper or platinum electrode that provides performance, improved ignitability, increased fuel economy, and lower emissions over your standard spark plug. It is completely corrosion-resistant and has anti-seizing properties. The unique cut in the center of this spark plug helps to direct the spark to the edge of the electrode for a faster, more efficient performance. The corrugated rib design helps prevent flashover, while the pure alumina silicate ceramic insulator provides superior strength and better heat transfer than your average spark plug. This model is highly durable, protected against electrical and chemical wear, and includes a triple seal to prevent leakage. One downside is that some customers reported the coils of their spark plug to be defective. Ensure to inspect your product upon delivery to double-check that there are no defects or manufacturing issues before installing it in your vehicle. HONORABLE MENTION ACDelco 1 Professional RAPIDFIRE Spark Plug This spark plug is designed for everyday use, and it can be used in most vehicles on the market today. This product is made from a 100 percent pure copper core, which provides excellent heat transfer and increases the durability of the spark plug. A ribless insulator is designed to improve the plug-to-boot seal and prevent leakage. A solid-state suppressor with a two-piece glass and brass seal reduces radio frequency interference and regulates spark energy for a longer electrode life. It also protects against high combustion pressures. The platinum on the center electrode maximizes the performance of this spark plug by enabling superior spark characteristics and reducing the voltage requirements of the vehicle's ignition system. Keep in mind that these are not iridium spark plugs, and so they will not work in every vehicle. Ensure to construct your owner's manual before purchasing to ensure that they are the correct option for your vehicle's engine. HONORABLE MENTION Champion Copper Plus Spark Plug The Champion Copper Plus C33-438 Spark Plug is a versatile option available to purchase in a value four-pack. This product features a nickel alloy center and a ground electrode that provides reliability and durability. The copper included in the center electrode allows for an increase in conductivity and heat control than your average, everyday spark plug. This spark plus makes an excellent choice for all types of automotive engines, particularly older models. In addition to vehicle engines, this spark plug can be used in lawn and garden applications and smaller engines. Make sure to consult your vehicle's owner's manual or instruction manual for your equipment before using these spark plugs as a replacement in your engine. One downside is that it is not an ideal option for many new vehicles and newer engines. Always make sure to consult your manual or contact your vehicle manufacturer before attempting to install new spark plugs. Our Verdict WHY TRUST US Our reviews are driven by a combination of hands-on testing, expert input, “wisdom of the crowd” assessments from actual buyers, and our own expertise. We always aim to offer genuine, accurate guides to help you find the best picks. For a high-quality spark plug, consider the NGK 6619 Iridium IX Spark Plugs, featuring excellent performance, power, efficiency, and reliability. Or, choose the Denso 4504 PK20TT Platinum Spark Plugs, an affordable platinum spark plug that delivers excellent durability and performance.
Types of Spark Plugs Copper Copper core spark plugs are the most basic and affordable type of spark plug that you can buy. These used to be the most common plug type on the market, but have recently been replaced by platinum and iridium spark plugs due to their superior performance, efficiency, and lifespan. While many modern engines simply cannot run copper spark plugs, there are a number of older engines that run better using copper plugs.
Platinum Platinum plugs deliver enhanced performance and fuel efficiency compared to copper plugs, but for a considerably cheaper price than iridium spark plugs. Much like iridium plugs, platinum spark plugs operate at a lower temperature than copper spark plugs. They can also last up to twice as long as basic copper plugs.
Double Platinum Double-platinum spark plugs provide even more performance, efficiency, and longevity than single-plated platinum plugs. What’s more, double-platinum plugs are still typically cheaper than iridium spark plugs. For an affordable upgrade from single platinum, just look for spark plugs that use platinum in both the electrode and cap. Iridium The best spark plugs on the market boast an iridium construction. Iridium spark plugs give you even better gas mileage, performance, reliability, and longevity than double-platinum plugs. Due to the advanced material and innovative technology integrated into iridium spark plugs, these plugs are priced higher than copper and platinum options. Iridium spark plugs are perfect to use on high-performance engines.
Double Iridium Double-iridium spark plugs are very much like the double-platinum ones. Double-iridium spark plugs have two discs made of rare metal to increase performance and durability. The design of these spark plugs is to deliver firepower essential for all kinds of driving conditions, including extreme heat or continual high-speeds. Double-iridium can provide up to four times the average life of service than a standard copper spark plug.
Key Features Material When you’re shopping for spark plugs, it’s important to consider which material best suits your needs. Copper is ideal for older model vehicles that feature a low-voltage distributor-based ignition. Platinum and iridium are best suited for modern engines without distributors. Platinum delivers a great mix of economy, performance, and longevity. Iridium offers an even better mix but at a higher cost. In the end, always use the plug specified by your vehicle’s manufacturer.
Size One important way that spark plugs are specified is by the size of the thread or nut. In the United States, typical thread and nut sizes are as follows: 10 millimeters (nut: 16 millimeters), 12 millimeters (nut: 14 millimeters, 16 millimeters, or 17.5 millimeters), 14 millimeters (nut: 16 millimeters or 20.63 millimeters), and 18 millimeters (nut: 20.63 millimeters).
Heat Range A spark plug is specified as “hot” if it’s a better heat insulator, and it’s classified as “cold” if it can conduct more heat out of the tip and lower its temperature. Generally, manufacturers denote the heat range of a spark plug with a number, with some brands using ascending numbers for hotter plugs and others doing the opposite for colder spark plugs.
Gap Style Spark plugs are usually engineered to have a spark gap which can be adjusted using a spark plug gapper tool. A single plug may be designed for several engines, necessitating a different gap for each. Spark plugs for cars typically gap between 0.6 and 1.8 millimeters (0.024 and 0.071 inches). Use a gap gauge to measure the plug’s gap to ensure that it’s within the specified range. Pricing
Under $3: There are several spark plugs available in this value-priced range. Buyers must do their homework before purchasing cheaper spark plugs due to the vastly varying degree of quality.
$3 to $9: The majority of spark plugs fall into this pricing segment. Most shoppers choose a spark plug priced in this range because they tend to offer an ideal blend of efficiency, longevity, performance, and value.
$10 and up: Spark plugs priced in this range tend to feature a durable construction using premium materials, advanced electrode designs, and unparalleled performance, efficiency, and longevity.
Tips
Have your vehicle information handy when shopping for new plugs to ensure you purchase the right spark plugs for your ride. Your owner’s manual or vehicle registration card should have the following information: model year, make, model, engine displacement, carburetor or fuel injection type, and cylinder count.
It’s a wise idea to replace your spark plug wires when you change your plugs. Faulty spark plugs can damage the wires, so swapping out both components at the same time will ensure that your engine receives the best ignition parts possible.
As tempting as it is, don’t always purchase the least expensive option for spark plugs. The best-quality spark plugs are usually more expensive because they guarantee optimal fuel economy, engine performance, longevity, and reliability.
Inspect your plugs to determine their condition. If the plugs look fine except for a red coating, this could be residual additives from poor-quality gas. Clean them off with a clean cloth and reinstall them. If the plug has black or heavy ash deposits around or on top of its center electrode, this means it must be replaced.
Before you remove your old plugs, clean the cylinder head around your plugs with a compressed air can or gun. This will blow away any dirt or deposits that may have collected on this area. This is important because dirt can enter the cylinder bore and score the wall and wear the rings.
Inspect the new spark plugs for any damage. Ensure the side electrode aligns with the center electrode and is straight. If any adjustment is required, use needle nose pliers to gently reposition it.
FAQs Q: How can you tell when spark plugs are operating at optimum temperature? If you are wondering how to tell whether your spark plugs are operating well before problems arise, look at their color. Usually, when the spark plug is a light tan or gray color, that should tell you that it is running at optimum temperature. In other words, your vehicle’s engine is in good condition. Q: How long do spark plugs last? The life-span of spark plugs varies by both manufacturer and vehicle. Yet, the spark plugs in most vehicles sold on the market today should last for 100,000 or more miles. To ensure you do not go past your spark plugs interval, research the type of spark plugs to learn whether they are suitable for your vehicle. Keep in mind that the spark plugs in most performance and luxury models tend to have shorter intervals. Q: How frequently should I change my spark plugs? This depends on the quality of spark plugs you have in your car. Top-quality spark plugs will last longer than lower-quality plugs. Most mechanics recommend you change your copper core spark plugs every 30,000 miles or every 50,000 miles for iridium core spark plugs. This interval may be shorter if your engine isn’t in top condition, so it’s vital to inspect your spark plugs for premature wear and change them accordingly. Q: Will a faulty spark plug turn on the check engine light? When your vehicle has a faulty spark plug, it can cause the check engine light to illuminate, signaling an issue. In some instances, the check engine light may even be flashing instead of a solid light. When the warning light appears, it is essential that you or a professional mechanic look into the cause. Q: What are the symptoms of a faulty spark plug? You may notice the following symptoms if your spark plugs need to be replaced: hesitation or backfiring during acceleration, decreased acceleration, rough idle, spark plug wires charred on the end that goes onto the plugs, a significant drop in fuel economy, and difficulties starting your engine. If your ride doesn’t run as well as it usually does, and you suspect it’s attributed to bad spark plugs, inspect the plugs yourself or have a mechanic do it.