1978 Cadillac Eldorado Spark Plugs

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Keep Your 1978 Cadillac Eldorado in Top Shape with Quality Spark Plugs

Whether you’re repairing or upgrading your Spark Plug, using high-quality parts is key to keeping your 1978 Cadillac Eldorado looking sharp and performing at its best. At Advance Auto Parts we carry a wide selection of dependable options, including Spark Plugs. Whether you’re replacing a damaged part or enhancing your truck’s style and protection, you’ll find exactly what you need to get the job done right.

Top-Rated Spark Plugs from Trusted Brands

Looking for a reliable Spark Plug? We’ve got you covered with options from brands you know and trust like Autolite, NGK, and Champion. For example, Autolite Spark Plugs start at just $3.99 with an average 4.6 star rating. NGK and Champion offer similar pricing and quality, backed by strong customer feedback. With over 92 reviews and a solid 4.4 star average, you can shop with confidence knowing other Cadillac Eldorado owners approve.

Competitive Prices and Extensive Inventory

The average price for a 1978 Cadillac Eldorado Spark Plug at Advance Auto Parts is around $7.29, with a range that starts at $3.99 and goes up to $10.49. With 10 options in stock from 6 trusted brands, finding the right fit is easy. Popular picks like ACDelco RAPIDFIRE Spark Plug, 4, ACDelco Conventional Spark Plug, R45XLS6, and Autolite Platinum Spark Plug: Enhanced Durability & Improved Performance, AP646 start at just $4.99 and offer a great balance of form and function.

Explore Related Parts

While you’re upgrading or replacing your Spark Plug, don’t forget to check out other key components like Ignition Boots and Ignition Coils and Boots. At Advance Auto Parts, we’re here to help you keep your 1978 Cadillac Eldorado in peak condition, inside and out.

Essential 1978 Cadillac Eldorado Spark Plugs

E3 – DiamondFire Spark Plug (E3.46): Enhanced Power & Fuel Efficiency (Part No.E3.46)

DiamondFire Spark Plug (E3.46): Enhanced Power & Fuel Efficiency

from

$8.49
The Spark Plugs are the product of years of fundamental research in the combustion field. The unique patented electrode configuration of these new The spark plugs increases the amount of combustion pressure created during each power stroke of an engine, which results in a marked increase in power output, fuel economy, and reduced emissions in all gasoline engines. E3.46 is a 14mm, 0.750 reach plug with a gasket seat. It fits a wide variety of applications from the 60s to early 90s, especially import. E3.46 is widely stocked in automotive retail stores. The automotive plugs have three legs securing the Diamond FIRE electrode to the shell. This allows for excellent heat transfer, and helps to create more turbulence in the cylinder. The patented Diamond FIRE side wire is proven to increase power, reduce fuel consumption and improve hydrocarbon emissions in long-term use.
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NGK – NGK G-Power Platinum Spark Plug (TR55GP): Enhanced Durability & Efficiency, 3403 (Part No.3403)

NGK G-Power Platinum Spark Plug (TR55GP): Enhanced Durability & Efficiency, 3403

from

$8.99
NGK G-Power Platinum spark plugs are the best single platinum spark plugs at an economical price. G-Power plugs feature a fine wire platinum center electrode and a trapezoidal cut ground electrode that offers increased durability, improved fuel efficiency, lower emissions, faster starts and quicker acceleration over conventional nickel spark plugs. An excellent upgrade for vehicles which used nickel alloy spark plugs originally. For better performance consider upgrading to a NGK Iridium IX plug. For even greater performance consider upgrading to a NGK RUTHENIUM HX plug.
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Autolite – Autolite Copper Resistor Spark Plug: Quick Starts & Smooth Acceleration, 66 (Part No.66)

Autolite Copper Resistor Spark Plug: Quick Starts & Smooth Acceleration, 66

from

$4.49
Autolite Copper spark plugs are designed to provide reliable performance and efficiency for your vehicle. Featuring a copper core center electrode, these spark plugs excel in thermal control and resist fouling, ensuring consistent operation. The high nickel alloy center and ground electrodes are built for extended life, while the high alumina multi-rib ceramic insulator enhances thermal conductivity and insulation strength. With a nickel-plated shell, these spark plugs resist corrosion, offering long-lasting durability. Engineered for quick starts and smooth acceleration, they enhance your driving experience while promoting better fuel economy, helping you save at the pump. The mid-projection standard center electrode design and flat seat type ensure compatibility with a wide range of applications, making these spark plugs a dependable choice for maintaining your vehicle’s performance.
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ACDelco – ACDelco Double Platinum Spark Plug, 41-828 (Part No.41-828)

ACDelco Double Platinum Spark Plug, 41-828

from

$11.99
ACDelco Gold (Professional) Double Platinum Spark Plug are a high quality alternative to Original Equipment (OE) parts. With a copper core and double platinum pads on the center electrode, these plugs are designed to deliver long-lasting performance. These premium aftermarket replacement spark plugs are manufactured to meet your expectations for fit, form, and function. ACDelco Gold (Professional) parts are manufactured to meet your expectations for fit, form, and function, making them a smart choice for General Motors vehicles, as well as most makes and models, including special applications. These high-quality parts are backed by General Motors. Some ACDelco Gold parts may have formerly appeared as ACDelco Professional.
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Accel – Accel HP Copper Spark Plug – 14mm Thread – .708 in Reach – Tapered Seat – 4 Pack, 0526-4 (Part No.0526-4)

Accel HP Copper Spark Plug - 14mm Thread - .708 in Reach - Tapered Seat - 4 Pack, 0526-4

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$25.29
ACCEL HP Spark Plugs are made with a Copper core which is a better conductor than Platinum and Iridium. They deliver a stronger spark especially in high performance applications where high combustion pressures are present. Copper is much better at dissipating heat than other materials which lessens the chance of a misfire. ACCEL HP Spark Plugs are gapable allowing you to open the gap exposing a larger flame kernel or close it if needed for high boost applications. All ACCEL HP Spark Plugs have machine rolled threads allowing for a more precise thread engagement and torque retention.
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DENSO – DENSO Iridium Power Spark Plug: Maximum Spark Energy, 0.4mm Iridium Tip, ITF16, 5330 (Part No.5330)

DENSO Iridium Power Spark Plug: Maximum Spark Energy, 0.4mm Iridium Tip, ITF16, 5330

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$12.99
The Iridium Power Spark Plug (ITF16) is engineered for unmatched performance and efficiency, featuring the world’s smallest 0.4mm Iridium Center Electrode for enhanced spark and maximum combustion. Its patented 360-degree laser welding ensures durability, while the U-groove and taper-cut ground electrode optimize flame propagation for superior ignition. Built to withstand extreme temperatures exceeding 4000 Deg F, this spark plug is burnished with nickel plating for exceptional corrosion resistance and high-temperature endurance. Designed for a wide range of applications, including classic and collector cars, it delivers superior performance with more horsepower, quicker starts, and fewer misfires under heavy loads. The advanced iridium technology enhances fuel efficiency, making it a cost-effective choice, while its low voltage requirement ensures reliable ignition with reduced energy consumption. Whether you’re seeking maximum power or improved fuel economy, this spark plug is built to perform under the most demanding conditions.
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DENSO – DENSO Platinum TT Spark Plug – PW16TT, 4501 (Part No.4501)

DENSO Platinum TT Spark Plug - PW16TT, 4501

from

$5.79
The Platinum TT Spark Plug with a Twin-Tip design is engineered to deliver superior combustion efficiency by enabling faster flame propagation for a more complete burn. Featuring a durable platinum center electrode tip, this spark plug ensures long-lasting performance and reliable ignition under various driving conditions. Its flat seat type provides a secure fit, enhancing overall engine stability and performance. Designed for precision and efficiency, this spark plug not only improves fuel combustion but also contributes to better fuel economy and reduced emissions. Ideal for drivers seeking enhanced engine responsiveness and durability, it offers exceptional value and reliability for your vehicle.
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ACDelco – ACDelco Conventional Spark Plug, R43XLS (Part No.R43XLS)

ACDelco Conventional Spark Plug, R43XLS

from

$6.49
ACDelco GM Original Equipment Conventional Spark Plugs are designed, engineered, and tested to rigorous standards, and are backed by General Motors. These Conventional Spark Plugs are designed for reliability and efficient performance, and are a high quality replacement for many vehicles on the road today. Their high-quality copper cores and outstanding suppression characteristics deliver reliable performance. They are also available for Marine applications. These premium aftermarket replacement spark plugs are manufactured to meet your expectations for fit, form, and function. ACDelco GM Original Equipment parts are the true OE parts installed during the production of or validated by General Motors for GM vehicles. Some ACDelco GM Original Equipment parts may have formerly appeared as GM Genuine Parts (OE) or ACDelco Professional.
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Motorcraft – Motorcraft Spark Plug: Enhanced Durability & Optimized Performance, SP-439-AX (Part No.SP-439-AX)

Motorcraft Spark Plug: Enhanced Durability & Optimized Performance, SP-439-AX

from

$13.99
Motorcraft Spark Plugs are precision-engineered to meet strict Ford standards, ensuring original equipment performance and reliability for Ford, Lincoln, and Mercury vehicles. Designed with a fine wire platinum center electrode and platinum ground electrode tip, these spark plugs deliver enhanced durability, reduce fuel consumption, and optimize emissions. The multi-rib insulator protects against misfires, while the tapered seat type ensures an exact fit for seamless installation. Resistant to oxidation and arc erosion, they are built to withstand service intervals of up to 100,000 miles, providing long-lasting performance and confidence on the road. Backed by Motorcraft’s Service Parts Warranty, these spark plugs help prevent false check engine lights and maintain peak engine efficiency. Crafted with high-quality materials, they are ideal for a broad range of applications, including domestic and import cars and trucks, making them a reliable choice for drivers seeking durability and optimized performance.
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Autolite – Autolite Copper Resistor Spark Plug: Quick Starts & Enhanced Durability, 847 (Part No.847)

Autolite Copper Resistor Spark Plug: Quick Starts & Enhanced Durability, 847

from

$4.49
Autolite Copper spark plugs are designed to deliver reliable performance and meet the demands of your vehicle with precision. Featuring a copper core center electrode, these spark plugs ensure excellent thermal control and resistance to fouling, while the high nickel alloy center and ground electrodes provide extended life and durability. The high alumina multi-rib ceramic insulator enhances thermal conductivity and insulation, offering increased strength and reliability. With a nickel-plated shell, these spark plugs resist corrosion for long-lasting performance. Engineered for good fuel economy, they help optimize fuel efficiency, saving you money without compromising on power. Additionally, their advanced design ensures smooth acceleration and consistent ignition, making them a dependable choice for maintaining peak engine performance. With a standard center electrode design, mid projection, and flat seat type, these spark plugs are built to deliver quick starts and enhanced durability for regular-grade applications.
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Champion – Champion Double Platinum Power Spark Plug RS12PYPB5 – Enhanced Durability & Performance, 7963 (Part No.7963)

Champion Double Platinum Power Spark Plug RS12PYPB5 - Enhanced Durability & Performance, 7963

from

$8.89
Champion Double Platinum Power spark plugs combine a platinum fine-wire center electrode with platinum center and ground electrodes and exclusive Heat-Active alloy, ensuring powerful performance, longer service life and precise spark focus for optimal combustion. Champion your engine with spark plugs engineered to improve efficiency and keep your vehicle running at its best.
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Autolite – Autolite Double Platinum Spark Plug: Enhanced Durability & Performance, APP605 (Part No.APP605)

Autolite Double Platinum Spark Plug: Enhanced Durability & Performance, APP605

from

$7.49
The Double Platinum Spark Plug is engineered for exceptional durability and performance, making it a top choice for distributor-less ignition system (DIS) engines. Featuring a platinum-to-platinum design, it minimizes gap erosion and reduces misfires, ensuring a longer service life compared to copper and standard platinum plugs. Its yttrium-enhanced ground electrode delivers superior heat transfer, maintaining durability under high temperatures and pressure. The high alumina ceramic insulator optimizes thermal conductivity and dielectric strength, while the multi-rib insulator prevents flash-over for reliable operation. With a mid-projection center electrode and tapered seat type, this performance-grade spark plug is built to handle demanding conditions. Both the center and ground electrode tips are crafted from platinum, ensuring consistent ignition and enhanced efficiency. Designed to deliver value and reliability, this spark plug is a smart upgrade for those seeking improved engine performance and longevity.
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DENSO – DENSO Iridium TT Spark Plug: Ultimate Endurance and Power, 0.4mm Iridium Tip, ITF16TT, 4715 (Part No.4715)

DENSO Iridium TT Spark Plug: Ultimate Endurance and Power, 0.4mm Iridium Tip, ITF16TT, 4715

from

$15.49
The Iridium TT Spark Plug combines the durability of an OE-style plug with the power and torque of high-performance engineering. Featuring the world’s smallest 0.4mm Iridium Center Electrode, it maximizes firing potential while the 0.7mm Needle Tip Ground Electrode promotes higher spark energy and minimizes heat quenching. Built with DENSO’s patented Iridium-Rhodium alloy formula, it offers unmatched durability and withstands extreme temperatures exceeding 4000 Deg F. The advanced 360-degree laser welding process ensures a robust bond and structural integrity, while the Twin-Tip Technology, derived from OE Super Ignition Plug design, blends a fine wire Iridium Center Electrode with a Needle Tip Platinum Ground Electrode for ultimate endurance. This spark plug delivers over 100,000 miles of reliable performance, enhanced fuel economy, and reduced emissions, making it an eco-friendly and cost-effective choice. With premium materials and a tapered seat type, the Iridium TT Spark Plug is engineered for optimal performance and long-lasting reliability.
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Autolite – Autolite Copper Resistor Spark Plug: Quick Starts & Enhanced Durability, 85 (Part No.85)

Autolite Copper Resistor Spark Plug: Quick Starts & Enhanced Durability, 85

from

$4.49
Autolite Copper spark plugs are expertly crafted to ensure reliable performance and long-lasting durability for your vehicle. Featuring a copper core center electrode, these plugs excel in thermal control and resist fouling, ensuring consistent operation. The high nickel alloy center and ground electrodes are designed for extended life, while the high alumina multi-rib ceramic insulator enhances thermal conductivity and provides superior insulation for added strength. With a nickel-plated shell, these spark plugs resist corrosion, making them ideal for long-term use. The mid-projection center electrode and flat seat type ensure a precise fit, while the resistor design minimizes electrical interference. Optimized for good fuel economy, these spark plugs help you maximize mileage and efficiency. Built with regular-grade materials and nickel-tipped electrodes, they deliver dependable performance and quick starts, meeting the demands of your vehicle or application.
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Champion – Champion Copper Plus Spark Plug RN14YC – Dependable Performance & Durability, 405 (Part No.405)

Champion Copper Plus Spark Plug RN14YC - Dependable Performance & Durability, 405

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$5.99
Champion Copper Plus spark plugs deliver dependable ignition performance with proven copper-core technology. The copper core electrode provides excellent conductivity and optimized heat control for consistent sparks while the coated shell protects against corrosion. Champion your engine with spark plugs engineered to improve efficiency and keep your vehicle running at its best.
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NGK – NGK G-Power Platinum Spark Plug: Enhanced Durability & Fuel Efficiency, 3207 (Part No.3207)

NGK G-Power Platinum Spark Plug: Enhanced Durability & Fuel Efficiency, 3207

from

$8.99
NGK G-Power Platinum spark plugs are the best single platinum spark plugs at an economical price. G-Power plugs feature a fine wire platinum center electrode and a trapezoidal cut ground electrode that offers increased durability, improved fuel efficiency, lower emissions, faster starts and quicker acceleration over conventional nickel spark plugs. An excellent upgrade for vehicles which used nickel alloy spark plugs originally. For better performance consider upgrading to a NGK Iridium IX plug. For even greater performance consider upgrading to a NGK RUTHENIUM HX plug.
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Motorcraft – Motorcraft Standard Spark Plug (AGS32C): Reliable Performance & Durability, SP-436 (Part No.SP-436)

Motorcraft Standard Spark Plug (AGS32C): Reliable Performance & Durability, SP-436

from

$4.49
Standard Spark Plug (AGS32C) by Motorcraft is the ultimate choice for reliable performance and durability, specifically engineered to meet Ford’s stringent standards. Designed as original equipment for Ford, Lincoln, and Mercury vehicles, these spark plugs ensure an exact fit while delivering enhanced durability, reduced fuel consumption, and optimized emissions. Crafted with high-quality nickel for both the center and ground electrode tips, they resist oxidation and arc erosion, ensuring long-lasting performance. The multi-rib insulator effectively prevents misfires, while the design helps avoid false check engine lights, providing peace of mind for drivers. With service intervals of up to 100,000 miles, these spark plugs offer exceptional value and convenience. Backed by Motorcraft’s Service Parts Warranty, they are ideal for domestic and import cars and trucks of all sizes, making them a versatile solution for almost any application. Trust Motorcraft to deliver the same reliable ignition components your vehicle was manufactured with.
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Champion – Champion Double Platinum Power Spark Plug RS12PYP – Enhanced Durability & Performance, 7401 (Part No.7401)

Champion Double Platinum Power Spark Plug RS12PYP - Enhanced Durability & Performance, 7401

from

$7.49
Champion Double Platinum Power spark plugs combine a platinum fine-wire center electrode with platinum center and ground electrodes and exclusive Heat-Active alloy, ensuring powerful performance, longer service life and precise spark focus for optimal combustion. Champion your engine with spark plugs engineered to improve efficiency and keep your vehicle running at its best.
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Motorcraft – Motorcraft Double Platinum Spark Plug: Enhanced Durability & Reliability, SP-439-A (Part No.SP-439-A)

Motorcraft Double Platinum Spark Plug: Enhanced Durability & Reliability, SP-439-A

from

$7.79
Double Platinum Spark Plug by Motorcraft is the ultimate choice for maintaining peak performance and reliability in your Ford, Lincoln, or Mercury vehicle. Engineered to meet strict Ford standards, these spark plugs feature platinum center and ground electrode tips for exceptional durability and resistance to oxidation and arc erosion. Designed to eliminate misfires, reduce fuel consumption, and optimize emissions, they ensure smooth engine operation while protecting against false check engine lights. The multi-rib insulator adds an extra layer of protection against misfires, while the exact fit guarantees seamless installation. With service intervals of up to 100,000 miles, these spark plugs deliver long-lasting performance and value. Backed by Motorcraft’s Service Parts Warranty, they are crafted with high-quality materials to provide reliable performance across a wide range of domestic and import applications. Choose Motorcraft spark plugs for the same trusted quality that was in your vehicle when it rolled off the assembly line.
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E3 – E3 DiamondFIRE Spark Plug: More Power & Fuel Efficiency, E3.52 (Part No.E3.52)

E3 DiamondFIRE Spark Plug: More Power & Fuel Efficiency, E3.52

from

$8.49
“The Premium DiamondFire Automotive Spark Plug is engineered to deliver exceptional performance and efficiency for your vehicle. Featuring E3’s patented Diamond Fire edge-to-edge ground electrode, it ensures a faster, more complete burn for smoother acceleration and idle. The innovative “”diamond-shaped”” side wire electrode enhances combustion by quickly igniting the air/fuel mixture, resulting in a larger and faster flame kernel. This translates to improved power output – up to 6% on average – and better fuel efficiency, saving you money while reducing engine carbon deposits. Constructed with durable nickel center and ground electrode tips, this spark plug is built to last. Its gasket seat type ensures a secure fit, and the pre-gapped design eliminates the need for adjustments, making installation hassle-free. With its advanced technology, this spark plug not only boosts engine performance but also contributes to a cleaner, more efficient combustion process.”
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Champion – Champion Platinum Power Spark Plug RN14PMC – Powerful Performance & Longevity, 3405 (Part No.3405)

Champion Platinum Power Spark Plug RN14PMC - Powerful Performance & Longevity, 3405

from

$5.99
Champion Platinum Power spark plugs deliver powerful performance with the exclusive Premium alloy that reaches and sustains the correct operating temperature. A fine-wire center electrode and V-trimmed ground electrode provides sharp spark focus and reliable ignition for consistent combustion under demanding conditions. Champion your engine with spark plugs engineered to improve efficiency and keep your vehicle running at its best.
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Autolite – Autolite Platinum Spark Plug (AP666): Enhanced Durability & Performance (Part No.AP666)

Autolite Platinum Spark Plug (AP666): Enhanced Durability & Performance

from

$4.99
The Platinum Spark Plug (AP666) is a high-performance solution designed to elevate your engine’s efficiency and reliability. Featuring a platinum center electrode firing tip, it ensures quicker firing, smoother starts, and improved fuel efficiency while preventing gap erosion for a longer service life. Its high alumina ceramic insulator enhances thermal conductivity and insulation, delivering superior strength under demanding conditions. The multi-rib insulator effectively prevents flash-over, while the nickel-plated shell resists corrosion, ensuring extended durability. With a mid-projection center electrode and tapered seat type, this spark plug is tailored for optimal performance in older engine applications and designs. The combination of platinum and nickel materials in the electrode tips guarantees consistent ignition and robust performance, making it a dependable choice for drivers seeking enhanced acceleration and reliability. Engineered for durability and efficiency, this spark plug is a smart investment for maintaining peak engine performance over time.
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Motorcraft – Motorcraft High-Performance Spark Plug: Enhances Fuel Efficiency, SP-541-AX (Part No.SP-541-AX)

Motorcraft High-Performance Spark Plug: Enhances Fuel Efficiency, SP-541-AX

from

$15.99
The Motorcraft High-Performance Spark Plug is meticulously crafted to deliver superior ignition performance and optimize fuel efficiency, ensuring your vehicle operates at its best. Featuring a fine wire center electrode and platinum tips on both the center and ground electrodes, this spark plug is designed for exceptional durability and consistent performance. Its tapered seat type ensures a secure fit, contributing to reliable starts and smooth engine operation. Engineered to enhance fuel economy, it helps you maximize every gallon while maintaining peak vehicle performance over time. Trust Motorcraft’s commitment to quality and efficiency to keep your engine running smoothly, making this spark plug a valuable addition to your vehicle’s maintenance routine.
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NGK – NGK V-Power Nickel Spark Plug (GR4): Enhanced Ignitability & Performance, 2635 (Part No.2635)

NGK V-Power Nickel Spark Plug (GR4): Enhanced Ignitability & Performance, 2635

from

$5.99
NGK V-Power spark plugs offer reliable performance and improved ignitability over standard nickel plugs. Engineered specifically for OE applications, the special V-cut nickel alloy center electrode and concave ground electrode of NGK’s V-Power spark plug increases ignitability providing quicker starts and smoother idle. NGK’s legendary high grade alumina silicate ceramic creates a stronger insulator for optimal dielectric performance. Trivalent metal plating ensures superior anti-corrosion and anti-seizing properties.
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Autolite – Autolite Copper Resistor Spark Plug: Quick Starts & Enhanced Durability, 606 (Part No.606)

Autolite Copper Resistor Spark Plug: Quick Starts & Enhanced Durability, 606

from

$4.49
Autolite Copper spark plugs are crafted to deliver reliable performance and quick starts, ensuring your vehicle meets its power demands with ease. Featuring a copper core center electrode, these spark plugs excel in thermal control and resist fouling, while the high nickel alloy center and ground electrodes provide extended life and durability. The high alumina multi-rib ceramic insulator enhances thermal conductivity and insulation, offering superior strength under demanding conditions. Designed with a corrosion-resistant nickel-plated shell, these spark plugs are built to withstand extended use. With a standard center electrode design, mid projection, and tapered seat type, they are engineered for compatibility and consistent performance. The inclusion of a resistor further enhances functionality, making these spark plugs a dependable choice for regular-grade applications.
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ACDelco – ACDelco Double Platinum Spark Plug, 41-902 (Part No.41-902)

ACDelco Double Platinum Spark Plug, 41-902

from

$11.49
ACDelco GM Original Equipment Double Platinum Spark Plugs are designed, engineered, and tested to rigorous standards, and are backed by General Motors. With a copper core and double platinum pads on the center electrode, these plugs are designed to deliver long-lasting performance. ACDelco GM Original Equipment parts are the true OE parts installed during the production or validated by General Motors for GM vehicles. Some ACDelco GM Original Equipment parts may have formerly appeared as GM Genuine Parts (OE) or ACDelco Professional.
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ACDelco – ACDelco Double Platinum Spark Plug, 41-802 (Part No.41-802)

ACDelco Double Platinum Spark Plug, 41-802

from

$9.49
ACDelco Professional Double Platinum Spark Plugs are premium aftermarket plugs, and are a high quality replacement for many vehicles on the road today. With a copper core and double platinum pads on the center electrode, these plugs are designed to deliver long-lasting performance. These premium aftermarket replacement spark plugs are manufactured to meet your expectations for fit, form, and function.
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NGK – NGK Iridium IX Spark Plug (TR55IX): Outstanding Acceleration & Durability, 7164 (Part No.7164)

NGK Iridium IX Spark Plug (TR55IX): Outstanding Acceleration & Durability, 7164

from

$14.99
NGK Iridium IX spark plugs are specifically designed for the performance enthusiast. Iridium IX provides outstanding acceleration, high fuel efficiency and durability. NGK Iridium IX plugs offer extreme ignitability and exceptional anti-fouling. Tapered cut ground electrode provides improved starting, idling and throttle response. The Iridium fine wire center electrode’s durability is six times harder than platinum. Iridium alloy’s extremely high melting point is perfect for today’s engines. For even greater performance consider upgrading to an NGK Ruthenium HX plug.
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Most Popular Spark Plugs for 1978 Cadillac Eldorados

Enhance your 1978 Cadillac Eldorado with one of the 10 Spark Plugs we have in stock, starting at just $3.99.

Champion – Champion Double Platinum Power Spark Plug RN14PMP5 – Enhanced Durability & Performance, 7031 (Part No.7031)

Champion Double Platinum Power Spark Plug RN14PMP5 - Enhanced Durability & Performance, 7031

from

$10.49
Champion Double Platinum Power spark plugs combine a platinum fine-wire center electrode with platinum center and ground electrodes and exclusive Heat-Active alloy, ensuring powerful performance, longer service life and precise spark focus for optimal combustion. Champion your engine with spark plugs engineered to improve efficiency and keep your vehicle running at its best.
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NGK – NGK V-Power Nickel Spark Plug (GR45): Enhanced Ignitability & Performance, 4268 (Part No.4268)

NGK V-Power Nickel Spark Plug (GR45): Enhanced Ignitability & Performance, 4268

from

$6.99
NGK V-Power spark plugs offer reliable performance and improved ignitability over standard nickel plugs. Engineered specifically for OE applications, the special V-cut nickel alloy center electrode and concave ground electrode of NGK’s V-Power spark plug increases ignitability providing quicker starts and smoother idle. NGK’s legendary high grade alumina silicate ceramic creates a stronger insulator for optimal dielectric performance. Trivalent metal plating ensures superior anti-corrosion and anti-seizing properties.
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Autolite – Autolite Double Platinum Spark Plug: Enhanced Durability & Performance, APP646 (Part No.APP646)

Autolite Double Platinum Spark Plug: Enhanced Durability & Performance, APP646

from

$7.49
Double Platinum Spark Plug offers enhanced durability and performance with its platinum-to-platinum design, effectively reducing gap erosion and misfires for a longer service life. Engineered for distributor-less ignition system (DIS) engines, it outperforms copper and standard platinum plugs. The yttrium-enhanced ground electrode ensures superior heat transfer, maintaining durability under high temperatures and pressure. Its high alumina ceramic insulator optimizes thermal conductivity and dielectric strength, while the multi-rib insulator prevents flash-over for reliable operation. Featuring a mid-projection center electrode and flat seat type, this performance-grade spark plug is built with platinum tips on both the center and ground electrodes for consistent ignition and efficiency. Designed to withstand demanding conditions, it delivers exceptional value for drivers seeking reliability and long-lasting performance.
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Autolite – Autolite Copper Resistor Spark Plug: Quick Starts & Enhanced Durability, 646 (Part No.646)

Autolite Copper Resistor Spark Plug: Quick Starts & Enhanced Durability, 646

from

$3.99
Autolite Copper spark plugs are designed to provide reliable performance and durability for your vehicle. Featuring a copper core center electrode, these spark plugs excel in thermal control and resist fouling, ensuring consistent operation. The high nickel alloy center and ground electrodes are engineered for extended life, while the mid-projection design optimizes spark delivery. A high alumina multi-rib ceramic insulator enhances thermal conductivity and insulation, offering superior strength under demanding conditions. The nickel-plated shell resists corrosion, adding to the plug’s longevity. With a flat seat type and built-in resistor, these spark plugs are a dependable choice for maintaining quick starts and meeting your vehicle’s performance needs.
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E3 – DiamondFire Spark Plug (E3.46): Enhanced Power & Fuel Efficiency (Part No.E3.46)

DiamondFire Spark Plug (E3.46): Enhanced Power & Fuel Efficiency

from

$8.49
The Spark Plugs are the product of years of fundamental research in the combustion field. The unique patented electrode configuration of these new The spark plugs increases the amount of combustion pressure created during each power stroke of an engine, which results in a marked increase in power output, fuel economy, and reduced emissions in all gasoline engines. E3.46 is a 14mm, 0.750 reach plug with a gasket seat. It fits a wide variety of applications from the 60s to early 90s, especially import. E3.46 is widely stocked in automotive retail stores. The automotive plugs have three legs securing the Diamond FIRE electrode to the shell. This allows for excellent heat transfer, and helps to create more turbulence in the cylinder. The patented Diamond FIRE side wire is proven to increase power, reduce fuel consumption and improve hydrocarbon emissions in long-term use.
See More

Autolite – Autolite Platinum Spark Plug: Enhanced Durability & Improved Performance, AP646 (Part No.AP646)

Autolite Platinum Spark Plug: Enhanced Durability & Improved Performance, AP646

from

$4.99
Autolite Platinum spark plugs are expertly crafted to deliver exceptional performance and durability for older engine applications. Featuring a platinum center electrode firing tip, these spark plugs resist gap erosion, ensuring a longer service life and consistent reliability. The high alumina ceramic insulator enhances thermal conductivity and insulation, providing superior strength under demanding conditions. A multi-rib insulator design prevents flash-over, while the nickel-plated shell offers outstanding corrosion resistance for extended durability. With a necked-down center electrode, these spark plugs fire quicker and cleaner, requiring less voltage for smoother starts, faster acceleration, and improved fuel efficiency. Designed with a mid-projection standard center electrode and a flat seat type, they are tailored for performance-grade applications. The combination of platinum and nickel materials ensures optimal conductivity and durability, making these spark plugs a smart choice for drivers seeking enhanced engine efficiency and long-lasting reliability.
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Dorman – Help – Dorman – Help Spark Plug Non-Foulers – 14mm Gasket Seat Long Reach, 42004 (Part No.42004)

Dorman - Help Spark Plug Non-Foulers - 14mm Gasket Seat Long Reach, 42004

from

$9.99
This spark plug non fouler is designed for easy installation on specified vehicles to protect spark plugs from fouling and damage. It is engineered for durability and reliable performance.
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ACDelco – ACDelco RAPIDFIRE Spark Plug, 4 (Part No.4)

ACDelco RAPIDFIRE Spark Plug, 4

from

$7.99
ACDelco Gold (Professional) RAPIDFIRE Spark Plugs are a high quality alternative to Original Equipment (OE) parts. These RAPIDFIRE Single Platinum Performance Spark Plugs are designed for everyday use and are a high quality replacement for many vehicles on the road today. These premium aftermarket spark plugs have high-quality suppressors that help prevent misfiring, an improved plug to boot seal, and a pure copper core for greater durability. These premium aftermarket replacement spark plugs are manufactured to meet your expectations for fit, form, and function. ACDelco Gold (Professional) parts are manufactured to meet your expectations for fit, form, and function, making them a smart choice for General Motors vehicles, as well as most makes and models, including special applications. These high-quality parts are backed by General Motors. Some ACDelco Gold parts may have formerly appeared as ACDelco Professional.
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ACDelco – ACDelco Conventional Spark Plug, R45XLS6 (Part No.R45XLS6)

ACDelco Conventional Spark Plug, R45XLS6

from

$6.49
ACDelco GM Original Equipment Conventional Spark Plugs are designed, engineered, and tested to rigorous standards, and are backed by General Motors. These Conventional Spark Plugs are designed for reliability and efficient performance, and are a high quality replacement for many vehicles on the road today. Their high-quality copper cores and outstanding suppression characteristics deliver reliable performance. They are also available for Marine applications. These premium aftermarket replacement spark plugs are manufactured to meet your expectations for fit, form, and function. ACDelco GM Original Equipment parts are the true OE parts installed during the production of or validated by General Motors for GM vehicles. Some ACDelco GM Original Equipment parts may have formerly appeared as GM Genuine Parts (OE) or ACDelco Professional.
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NGK – NGK G-Power Platinum Spark Plug (GR45GP): Enhanced Durability & Efficiency, 3142 (Part No.3142)

NGK G-Power Platinum Spark Plug (GR45GP): Enhanced Durability & Efficiency, 3142

from

$5.99
NGK G-Power Platinum spark plugs are the best single platinum spark plugs at an economical price. G-Power plugs feature a fine wire platinum center electrode and a trapezoidal cut ground electrode that offers increased durability, improved fuel efficiency, lower emissions, faster starts and quicker acceleration over conventional nickel spark plugs. An excellent upgrade for vehicles which used nickel alloy spark plugs originally. For better performance consider upgrading to a NGK Iridium IX plug. For even greater performance consider upgrading to a NGK RUTHENIUM HX plug.
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Top-Rated Spark Plug Brands For Your 1978 Cadillac Eldorado

When it comes to finding the perfect Spark Plug for your 1978 Cadillac Eldorado, Advance Auto Parts has you covered with a wide selection of high-quality OEM and aftermarket options from 6 trusted brands. We carry the most popular Spark Plug brands including NGK, Champion, and Autolite, and more, all known for their exceptional customer ratings (average brand rating of 4.8 stars) and competitive prices, as low as $3.99. Purchasing a Spark Plug from us here at Advance Auto Parts is a smart move for both you and your 1978 Cadillac Eldorado, providing peace of mind with parts that meet or exceed OEM standards.

Popular NGK 1978 Cadillac Eldorado Spark Plugs

If you’re looking for a top-quality Spark Plug for your 1978 Cadillac Eldorado, Advance Auto Parts has exactly what you need with our selection of NGK Spark Plugs. We have 1 NGK Spark Plugs in stock for this fitment, all known for their durability and precision fit. With prices starting at just $6.99, you’ll find the perfect Spark Plug for your needs and budget. NGK Spark Plugs for the 1978 Cadillac Eldorado come highly rated, with over 4 customer reviews and an impressive average rating of 4.8 stars. Choosing a NGK Spark Plug from Advance Auto Parts is a smart move to ensure quality and value for your vehicle.

Top-Quality Champion 1978 Cadillac Eldorado Spark Plugs

For those in search of a high-quality Spark Plug for their 1978 Cadillac Eldorado, Advance Auto Parts offers a great selection of Champion Spark Plugs. With 1 Champion Spark Plugs in stock, you can trust you’re getting top-tier parts designed for durability and a perfect fit. Prices for these Spark Plugs start at just $10.49, giving you a range of options to suit your budget. Backed by over 8 customer ratings and an average rating of 4.8 stars, Champion Spark Plugs provide both reliability and excellent performance. Choosing a Champion Spark Plug from Advance Auto Parts is a smart investment in your vehicle’s performance and longevity.

FAQs for 1978 Cadillac Eldorado Spark Plugs

What are the best-selling Spark Plugs for 1978 Cadillac Eldorados?

Out of 10 Spark Plugs that fit 1978 Cadillac Eldorados, the following parts are the top sellers:

What’s the price range for 1978 Cadillac Eldorado Spark Plugs?

The prices of Spark Plugs for the 1978 Cadillac Eldorado range from $3.99 up to $10.49 for the most premium parts.

What is the average price of a Spark Plug for a 1978 Cadillac Eldorado?

The average price for Spark Plugs for the 1978 Cadillac Eldorado is $7.29. Keep in mind the variety of part types within our Spark Plug category, where you are likely to find a wide range of prices across a variety of parts and components.

Does Advance Auto Parts sell Spark Plugs for other Cadillac Eldorado model years?

Yes, we carry Spark Plugs for 48 model years of Cadillac Eldorados between 1953 and 2002. The following model years are the most popular for Spark Plug purchases: 2002, 2001, 2000, 1999, 1998, 1997, 1996, 1995, and 1994.

Does Advance Auto Parts sell Spark Plugs for any other 1978 Cadillac models?

Yes. We stock Spark Plugs for 3 other popular 1978 Cadillac models. Some of the most popular are 1978 DeVille Spark Plugs, 1978 Seville Spark Plugs, 1978 Fleetwood Spark Plugs, and 1978 Commercial Chassis Spark Plugs.

What are the top-rated Spark Plugs that fit the 1978 Cadillac Eldorado?

The one 1978 Cadillac Eldorado Spark Plug we have in stock is the Autolite Copper Resistor Spark Plug: Quick Starts & Enhanced Durability, 646. It is rated 4.5 stars and costs $3.99.

What types of Spark Plugs do you sell for my 1978 Cadillac Eldorado?

We currently have just 1 Spark Plug in stock for a 1978 Cadillac Eldorado, and as of 8/2/26, it is a Spark Plug.

Can I get help with 1978 Cadillac Eldorado Spark Plug orders?

Contact our customer support team by chat or phone, through the help desk page, where you can find instant answers about Cadillac Spark Plugs and more.

What is your return policy for Cadillac Eldorado Spark Plugs?

Advance Auto Parts keeps returns simple. For new Cadillac Eldorado Spark Plugs and accessories, your online orders can be returned, in their original condition, within 45 days. For requirements, see the returns page.