2004 Volvo S40 Spark Plugs

Your 2004 Volvo S40 might be the best vehicle you’ve ever owned. Or you may just be struggling to keep it highway-approved. No matter the situation, Advance Auto Parts has the Spark Plugs you desperately need.

We currently carry 42 Spark Plugs to choose from for your 2004 Volvo S40, and our inventory prices range from as little as $2.29 up to $18.99.

On top of low prices, Advance Auto Parts offers 6 different trusted brands of Spark Plugs for the 2004 Volvo S40. We only sell parts from trusted brands like Autolite so that you can find quality parts you can count on.

Don’t take our word for it – check out customer ratings and reviews to buy with confidence. We have 2,675 reviews on our Spark Plugs for the 2004 Volvo S40 from previous customers.

Have parts delivered straight to your home, or find the nearest Advance Auto Parts store to check out our Spark Plugs stock in-person!

Spark Plugs for Your 2004 Volvo S40

DENSO – Iridium Long-Life Spark Plug: OE Performance, last 100K+ Miles, SK20HR11 (Part No.3421)

Iridium Long-Life Spark Plug:  OE Performance, last 100K+ Miles, SK20HR11

from

$11.49
Manufactured to the strictest OE performance, durability and emissions standards.

Product Features:
  • Latest OE technology with DENSO’s patented Iridium Alloy (90% Ir) and fine wire center electrode
  • Platinum ground electrode for extended life
  • DENSO Patented 360 degree laser welding process: Ensuring exceptional quality bond and structural strength with the Iridium Center Electrode
  • Sustained spark performance over 100,000 miles
  • Lasts up to three times as long as conventional plugs
  • Endures extreme temperatures greater than 4,000 degrees F associated with high-performance ignition and special fuel systems
  • Iridium Long Life
  • Enhanced Engine Performance: Enjoy more horsepower, faster and easier starts, and fewer misfires under heavy loads, thanks to the advanced properties of DENSO’s Iridium alloy.
  • Fuel Efficiency: Experience better conservation of fuel at all times, contributing to overall vehicle efficiency and cost savings.
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NGK – G-Power Spark Plug: Single Platinum Tip Design, BKR6EGP (Part No.7092)

G-Power Spark Plug: Single Platinum Tip Design, BKR6EGP

from

$6.29
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

Product Features:
  • SINGLE PLATINUM TIP: Fine wire 0.6 millimeter platinum tip center electrode ensures improved durability and a consistently stable spark
  • PLATINUM ALLOY: G-Power platinum provides exceptional value with increased performance and longer service intervals than factory nickel plugs
  • TRAPEZOIDAL CUT GROUND ELECTRODE: Reduces quenching design produces improved ignitability and performance
  • SOLID COPPER CORE: 98% pure copper core offers superior heat dissipation, conductivity and ultra wide heat ranges
  • COLD-ROLLED THREADS: Prevents cross-threading and damage to cylinder heads
  • RECOMMENDED USAGE: Lower cost alternative to double precious metal spark plugs or as an upgrade to OE nickel alloy spark plugs
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NGK – OE Series V-Power Nickel Spark Plug: V-Groove Tip Design, BKR6E (Part No.6962)

OE Series V-Power Nickel Spark Plug: V-Groove Tip Design, BKR6E

from

$4.99
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

Product Features:
  • ACTUAL OE or EQUIVALENT DESIGN: OEM quality construction nickel alloy center electrode with V-groove provides consistent performance
  • RECOMMENDED USAGE: Best for vehicles with OE nickel alloy plugs, not recommended on vehicles with factory precious metal plugs
  • NGK’s OE CERAMIC TECHNOLOGY: High grade alumina silicate ceramic creates a stronger insulator for optimal dielectric performance
  • SOLID COPPER CORE: 98% pure copper core offers superior heat dissipation, conductivity and ultra wide heat ranges
  • COLD-ROLLED THREADS: Prevents cross-threading and damage to cylinder heads
  • TRIVALENT METAL PLATING: Delivers superior anti-corrosion and anti-seizing properties, ensuring ease of installation and removal
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NGK – Iridium IX Spark Plug: Single Iridium Fine Wire, BKR6EIX (Part No.6418)

Iridium IX Spark Plug: Single Iridium Fine Wire, BKR6EIX

from

$11.99
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.

Product Features:
  • SINGLE IRIDIUM TIP: Fine wire 0.6 millimeter iridium tip center electrode ensures high durability and a consistently stable spark
  • IRIDIUM ALLOY CENTER ELECTRODE: Iridium’s density (6x that of platinum) and extremely high melting point is perfect for modern high efficiency engines
  • TAPERED CUT GROUND ELECTRODE: Reduced quenching design produces outstanding ignitability, improved acceleration, fuel efficiency and durability
  • SOLID COPPER CORE: 98% pure copper core offers superior heat dissipation, conductivity and ultra wide heat ranges
  • TRIVALENT METAL PLATING: Delivers superior anti-corrosion and anti-seizing properties, ensuring ease of installation and removal
  • RECOMMENDED USAGE: Modified or high performance applications, or as an upgrade to OE nickel alloy spark plugs
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DENSO – Iridium TT Spark Plug: Ultimate Endurance and Power, 0.4mm Iridium Tip, last 100K+ Miles, IKH20TT (Part No.4704)

Iridium TT Spark Plug: Ultimate Endurance and Power, 0.4mm Iridium Tip, last 100K+ Miles, IKH20TT

from

$10.99
Durability of an OE style plug combined with Power & Torque of high performance.

Product Features:
  • 0.4mm Iridium Center Electrode: World’s Smallest Diameter that maximizes firing potential
  • 0.7mm Needle Tip Ground Electrode: Promotes higher spark energy and less heat quenching
  • DENSO Patented Optimized Iridium-Rhodium Alloy Formula: Highest concentration of Iridium vs. competitors for greater durability
  • DENSO Patented 360 degree laser welding process: Ensuring exceptional quality bond and structural strength with the Iridium Center Electrode
  • Durability of an OE style plug combined with Power & Torque of high performance.
  • Withstands temperatures greater than 4000° Fahrenheit
  • Iridium TT
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DENSO – Iridium Power Spark Plug: Maximum Spark Energy, 0.4mm Iridium Tip, IK20 (Part No.5304)

Iridium Power Spark Plug: Maximum Spark Energy, 0.4mm Iridium Tip, IK20

from

$11.79
Increased performance with World’s smallest Iridium Center Eletrode (0.4mm).

Product Features:
  • World’s smallest Iridium Center Electrode (0.4mm) for improved spark for maximum combustion
  • Patented 360-degree laser welding assembly process
  • U-groove and taper cut ground electrode to maximize flame propagation.
  • Withstands temperatures greater than 4000° Fahrenheit
  • Burnished nickel plating for high temperature endurance and superior corrosion resistance
  • Wide range of part numbers for thousands of applications, including classic and collector cars
  • Iridium Power
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NGK – OE Series Standard Nickel Spark Plug: Conventional Tip Design, BKR6ES (Part No.6364)

OE Series Standard Nickel Spark Plug: Conventional Tip Design, BKR6ES

from

$4.49
NGK Standard spark plugs (in the iconic NGK ‘yellow box’ packaging) are a proven OE cornerstone and technology customers have relied on for decades. Engineered specifically for OE applications, NGK Standard spark plugs provide OE quality nickel alloy reliable performance and design. NGK’s legendary high grade alumina silicate ceramic creates a stronger insulator for optimal dielectric performance, while triple gasket sealing prevents combustion gas leakage. Solid 98% pure copper core offers superior heat dissipation, conductivity and ultra wide heat ranges. Trivalent metal plating ensures superior anti-corrosion and anti-seizing properties.

Product Features:
  • ACTUAL OE or EQUIVALENT DESIGN: OEM quality construction nickel alloy center electrode provides consistent performance
  • RECOMMENDED USAGE: Best for vehicles with OE nickel alloy plugs, not recommended on vehicles with factory precious metal plugs
  • NGK’s OE CERAMIC TECHNOLOGY: High grade alumina silicate ceramic creates a stronger insulator for optimal dielectric performance
  • SOLID COPPER CORE: 98% pure copper core offers superior heat dissipation, conductivity and ultra wide heat ranges
  • COLD-ROLLED THREADS: Prevents cross-threading and damage to cylinder heads
  • TRIVALENT METAL PLATING: Delivers superior anti-corrosion and anti-seizing properties, ensuring ease of installation and removal
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Autolite – Racing Resistor Spark Plug: Enables Performance, Handles Intense Conditions (Part No.AR3923)

Racing Resistor Spark Plug: Enables Performance, Handles Intense Conditions

from

$4.99
The ground electrode is cut-back from the center electrode to provide a gap. The face of the ground electrode is concave to provide a constant gap to the center electrode. This plug is designed use in all aftermarket cylinder heads used in different types of racing venues including oval and road racing.

Product Features:
  • Opens spark face for better ignitability of flame kernel
  • Retains less heat, transfers heat to shell faster – reduces risk of pre-ignition
  • Dyno testing has shown proven power gains
  • Cut-back ground electrode evolved from practice of grinding back the side electrode
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Autolite – Copper Spark Plug: Delivers Quick Starts, Good Fuel Economy, Smooth Acceleration (Part No.5325)

Copper Spark Plug: Delivers Quick Starts, Good Fuel Economy, Smooth Acceleration

from

$3.49
Autolite has over 100 years of engineering experience and has sold over 11 billion plugs. Guaranteed to deliver quick starts, good fuel economy and smooth acceleration, Autolite Copper Core spark plugs are designed to meet or exceed OES design requirements. Consider upgrading to Autolite Platinum, Double Platinum or Iridium XP plugs for improved engine performance. Copper core plugs are the industry standard.

Product Features:
  • Copper-glass seal bonds insulator, terminal post center electrode together; assures full required voltage at spark gap; gas-tight seal (100% leak proof)
  • Multi-rib insulator reduces danger of “flash-over”
  • One-piece terminal post adds strength
  • Resistor reduces radio frequency interference (RFI) and electrode erosion
  • Quick Starts: Autolite Copper Core spark plugs are engineered to ensure your engine starts quickly and reliably every time.
  • Good Fuel Economy: Designed to optimize fuel efficiency, these spark plugs help you get the most out of every gallon of gas.
  • Smooth Acceleration: Experience seamless and smooth acceleration with Autolite Copper Core spark plugs, enhancing your driving experience.
  • OES Design Compliance: These spark plugs are crafted to meet or exceed Original Equipment Service (OES) design requirements, ensuring high-quality performance.
  • Industry Standard: Autolite Copper Core spark plugs are recognized as the industry standard, backed by over 100 years of engineering expertise and the sale of over 11 billion plugs.
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NGK – Ruthenium HX High Ignitability Spark Plug: PSPE Tip Design, LFR6BHX (Part No.93420)

Ruthenium HX High Ignitability Spark Plug: PSPE Tip Design, LFR6BHX

from

$14.79
NGK Ruthenium HX High Ignitability spark plugs are the best in class plug for todays modern vehicles. Patented Ruthenium technology offers the most advance tip technology and delivers the highest performance and life expectancy. Created from advanced OE technology as a high ignitability plug; Ruthenium HX spark plugs come with patented, specialized OEM DFE and PSPE tip designs. NGK Ruthenium HX High Ignitability spark plugs provide a more complete fuel burn resulting in a quicker throttle response, smoother idle and better cold starts. Ruthenium center electrode provides industry leading durability.

Product Features:
  • HIGH IGNITABILITY PROJECTED SQUARE PLATINUM ELECTRODE DESIGN: Combines 0.6 millimeter ruthenium center with a unique cut-back PSPE ground electrode
  • RUTHENIUM ALLOY CENTER ELECTRODE: NGK’s patented ruthenium technology produces maximum performance, ignitability & durability at high temperatures
  • PSPE DESIGN: Projected square platinum electrode shape of the ground electrode provides the best ignitability and service life for high heat engines
  • SOLID COPPER CORE: 98% pure copper core offers superior heat dissipation, conductivity and ultra wide heat ranges
  • TRIVALENT METAL PLATING: Delivers superior anti-corrosion and anti-seizing properties, ensuring ease of installation and removal
  • RECOMMENDED USAGE: Modern vehicles using OE PSPE type spark plugs or for those seeking an aftermarket plug with the latest OE technology
  • High Ignitability Design: Ensures a more complete fuel burn, resulting in quicker throttle response, smoother idle, and better cold starts.
  • Specialized OEM Tip Designs: Features patented DFE and PSPE tip designs for optimal performance in modern vehicles.
  • Industry-Leading Durability: Ruthenium center electrode provides exceptional durability, making it a reliable choice for long-term use.
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DENSO – Double Platinum Spark Plug: OE Performance, lasts 60K+ Miles, PK20PR-P8 (Part No.3245)

Double Platinum Spark Plug:  OE Performance, lasts 60K+ Miles, PK20PR-P8

from

$9.79
Manufactured to the strictest OE performance, durability and emissions standards.

Product Features:
  • OE grade platinum on both center and ground electrods
  • Premium shell construction with machine-rolled threads
  • Superior thermal conductivity
  • Sustained spark performance over 60,000 miles
  • Reduced secondary required voltage, increased ignition efficiency
  • Satisfied customers, reduced shop comebacks
  • Double Platinum
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DENSO – Iridium Long-Life Spark Plug: OE Performance, last 100K+ Miles, SK20PR-A8 (Part No.3403)

Iridium Long-Life Spark Plug:  OE Performance, last 100K+ Miles, SK20PR-A8

from

$16.49
Manufactured to the strictest OE performance, durability and emissions standards.

Product Features:
  • Latest OE technology with DENSO’s patented Iridium Alloy (90% Ir) and fine wire center electrode
  • Platinum ground electrode for extended life
  • DENSO Patented 360 degree laser welding process: Ensuring exceptional quality bond and structural strength with the Iridium Center Electrode
  • Sustained spark performance over 100,000 miles
  • Lasts up to three times as long as conventional plugs
  • Endures extreme temperatures greater than 4,000 degrees F associated with high-performance ignition and special fuel systems
  • Iridium Long Life
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Autolite Iridium – Iridium XP Finewire Spark Plug: Improved Durability, More Focused Ignition (Part No.XP5325)

Iridium XP Finewire Spark Plug: Improved Durability, More Focused Ignition

from

$9.99
Our best spark plug! Autolite has over 100 years of engineering experience and has sold over 11 billion plugs. Designed and engineered in the USA, the Autolite Iridium XP spark plugs feature an iridium-enhanced 0.6mm finewire design and patented platinum sidewire technology to provide better overall durability and a more focused ignition for enhanced ignitability and performance. Features double Iridium-enhanced alloy technology center electrode for improved durability and wear resistance.

Product Features:
  • 0.6 mm finewire design improves ignitability
  • Patented V-trimmed platinum sidewire technology resists wear
  • OE equivalent design is engineered for every engine
  • Designed for better overall durability with virtually no gap erosion
  • Double Iridium-Enhanced Alloy Technology Center Electrode: Offers improved durability and wear resistance for a longer-lasting spark plug.
  • Designed and Engineered in the USA: Reflects over 100 years of Autolite’s engineering experience and expertise.
  • Gasket Seat Type: Ensures a secure and proper fit for optimal performance.
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Autolite – Platinum Spark Plug: Fires Cleaner, Easier Starts, Quicker Acceleration (Part No.AP5325)

Platinum Spark Plug: Fires Cleaner, Easier Starts, Quicker Acceleration

from

$4.79
With over 100 years of engineering expertise and over 11 billion plugs sold, Autolite Platinum spark plugs are designed and engineered in the USA to deliver exceptional performance. Featuring a high nickel alloy side electrode that maintains a precise gap and a full platinum tip that ensures virtually no gap erosion, these spark plugs offer long-lasting durability. The necked-down center electrode fires quicker and cleaner with less voltage, resulting in easier starts, quicker acceleration, and improved fuel economy compared to standard plugs.

Product Features:
  • High nickel alloy side electrode maintains precise gap
  • Full platinum tip assures virtually no gap erosion for long life
  • Necked-down center electrode fires quicker, cleaner with less voltage for easier starts, quicker acceleration and improved fuel economy (as compared to standard plugs)
  • Improved Fuel Economy: Designed to enhance fuel efficiency compared to standard plugs.
  • Engineered in the USA: Backed by over 100 years of engineering expertise and over 11 billion plugs sold.
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DENSO – Iridium TT Spark Plug: Ultimate Endurance and Power, 0.4mm Iridium Tip, last 100K+ Miles, IK20TT (Part No.4702)

Iridium TT Spark Plug: Ultimate Endurance and Power, 0.4mm Iridium Tip, last 100K+ Miles, IK20TT

from

$10.99
Durability of an OE style plug combined with Power & Torque of high performance.

Product Features:
  • 0.4mm Iridium Center Electrode: World’s Smallest Diameter that maximizes firing potential
  • 0.7mm Needle Tip Ground Electrode: Promotes higher spark energy and less heat quenching
  • DENSO Patented Optimized Iridium-Rhodium Alloy Formula: Highest concentration of Iridium vs. competitors for greater durability
  • DENSO Patented 360 degree laser welding process: Ensuring exceptional quality bond and structural strength with the Iridium Center Electrode
  • Durability of an OE style plug combined with Power & Torque of high performance.
  • Withstands temperatures greater than 4000┬░ Fahrenheit
  • Iridium TT
  • Ultimate Endurance and Power: The DENSO Iridium TT Spark Plug features a 0.7mm Iridium Tip, ensuring over 100,000 miles of uncompromised performance.
  • Advanced Twin-Tip Technology: Developed from Original Equipment Specification Super Ignition Plug (SIP) design, combining a Fine Wire Iridium Center Electrode with a Needle Tip Platinum Ground Electrode.
  • Enhanced Fuel Economy and Lower Emissions: Drive around the Earth over 4 times with improved fuel efficiency and reduced emissions.
  • Premium Materials: Features an Iridium Center Electrode Tip and a Flat Seat Type for optimal performance and durability.
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Autolite Iridium – Iridium XP Finewire Spark Plug: Improved Durability, More Focused Ignition (Part No.XP3923)

Iridium XP Finewire Spark Plug: Improved Durability, More Focused Ignition

from

$9.99
Our best spark plug! Autolite has over 100 years of engineering experience and has sold over 11 billion plugs. Designed and engineered in the USA, the Autolite Iridium XP spark plugs feature an iridium-enhanced 0.6mm finewire design and patented platinum sidewire technology to provide better overall durability and a more focused ignition for enhanced ignitability and performance. Features double Iridium-enhanced alloy technology center electrode for improved durability and wear resistance.

Product Features:
  • 0.6 mm finewire design improves ignitability
  • Patented V-trimmed platinum sidewire technology resists wear
  • OE equivalent design is engineered for every engine
  • Designed for better overall durability with virtually no gap erosion
  • Double Iridium-Enhanced Alloy Technology Center Electrode: Offers improved durability and wear resistance for a longer-lasting spark plug.
  • Designed and Engineered in the USA: Reflects over 100 years of Autolite’s engineering experience and expertise.
  • Gasket Seat Type: Ensures a secure and proper fit for optimal performance.
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Autolite – Double Platinum Spark Plug: Platinum Firing, Superior Durability, Longer Life (Part No.APP5325)

Double Platinum Spark Plug: Platinum Firing, Superior Durability, Longer Life

from

$6.79
Autolite has over 100 years of engineering experience and has sold over 11 billion plugs. Designed and engineered in the USA, Autolite Double Platinum spark plugs feature platinum-to-platinum firing which virtually eliminates gap erosion, reduces misfires and increases durability of the plug. Consider upgrading to Autolite Iridium XP spark plugs for increased performance.

Product Features:
  • Works to optimize engine performance for a longer life and improved fuel economy
  • OE design
  • Full-platinum tips; platinum on both the center and side electrodes to promote reduced gap wear
  • Platinum ball welding process provides a consistent point of contact for enhanced adhesion
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Autolite – Platinum Spark Plug: Fires Cleaner, Easier Starts, Quicker Acceleration (Part No.AP3923)

Platinum Spark Plug: Fires Cleaner, Easier Starts, Quicker Acceleration

from

$4.79
With over 100 years of engineering expertise and more than 11 billion plugs sold, Autolite Platinum spark plugs are designed and engineered in the USA to deliver exceptional performance. Featuring a high nickel alloy side electrode that maintains a precise gap and a full platinum tip that ensures virtually no gap erosion, these spark plugs offer long-lasting durability. The necked-down center electrode fires quicker and cleaner with less voltage, resulting in easier starts, quicker acceleration, and improved fuel economy compared to standard plugs.

Product Features:
  • High nickel alloy side electrode maintains precise gap
  • Full platinum tip assures virtually no gap erosion for long life
  • Necked-down center electrode fires quicker, cleaner with less voltage for easier starts, quicker acceleration and improved fuel economy (as compared to standard plugs)
  • Exceptional Performance: Designed and engineered in the USA, Autolite Platinum Spark Plugs deliver superior performance with over 100 years of engineering expertise and more than 11 billion plugs sold.
  • Gasket Seat Type: Equipped with a gasket seat type, these spark plugs provide a secure and effective seal for optimal engine performance.
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NGK – Iridium IX Spark Plug: Single Iridium Fine Wire, LFR6AIX-11 (Part No.6619)

Iridium IX Spark Plug: Single Iridium Fine Wire, LFR6AIX-11

from

$12.99
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 c

Product Features:
  • SINGLE IRIDIUM TIP: Fine wire 0.6 millimeter iridium tip center electrode ensures high durability and a consistently stable spark
  • IRIDIUM ALLOY CENTER ELECTRODE: Iridium’s density (6x that of platinum) and extremely high melting point is perfect for modern high efficiency engines
  • TAPERED CUT GROUND ELECTRODE: Reduced quenching design produces outstanding ignitability, improved acceleration, fuel efficiency and durability
  • SOLID COPPER CORE: 98% pure copper core offers superior heat dissipation, conductivity and ultra wide heat ranges
  • TRIVALENT METAL PLATING: Delivers superior anti-corrosion and anti-seizing properties, ensuring ease of installation and removal
  • RECOMMENDED USAGE: Modified or high performance applications, or as an upgrade to OE nickel alloy spark plugs
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E3 – DiamondFIRE Automotive Spark Plug: More Power, Saves Gas (Part No.E3.68)

DiamondFIRE Automotive Spark Plug: More Power, Saves Gas

from

$6.99
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. E3.68 is a 14mm, 1.000 reach plug with a gasket seat. It fits a wide variety of late model applications, especially Hemi applications. E3.68 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.

Product Features:
  • E3’s Diamond Fire edge to edge ground electrode provides maximum performance with increased efficiency and a faster more complete burn
  • Smoother Acceleration & Idle – The faster flame initiated by the The spark plug results in a more complete burn of the ingested fuel charge. More pressure is created against the piston more fuel is put to work
  • Energy – Power output improved up to 6% on average in the typical operating ranges. Results will vary.
  • Efficiency – The “diamond shaped” side wire electrode projects the combustion spark in a way that more quickly ignites the air/fuel mixture, thereby creating a significantly faster and larger flame kernel. The result is that more fuel is put to work durin
  • E3’s patented Diamond Fire Technology provides a cleaner burning combustion, which translates into fuel savings and reduced engine carbon deposits
  • The Spark Plugs are pre-gapped at the factory and cannot be adjusted.
  • Wide Compatibility: E3.68 spark plugs are 14mm with a 1.000 reach and a gasket seat, fitting a wide variety of late model applications, especially Hemi engines.
  • Enhanced Heat Transfer: The three legs securing the Diamond FIRE electrode to the shell ensure excellent heat transfer and create more turbulence in the cylinder for better combustion.
  • Widely Available: E3.68 spark plugs are widely stocked in automotive retail stores, making them easily accessible for consumers.
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Autolite – Copper Spark Plug: Delivers Quick Starts, Good Fuel Economy, Smooth Acceleration (Part No.3923)

Copper Spark Plug: Delivers Quick Starts, Good Fuel Economy, Smooth Acceleration

from

$3.49
Autolite Copper spark plugs deliver quick starts, good fuel economy and smooth acceleration.

Product Features:
  • Copper-glass seal bonds insulator, terminal post center electrode together; assures full required voltage at spark gap; gas-tight seal (100% leak proof)
  • Multi-rib insulator reduces danger of “flash-over”
  • One-piece terminal post adds strength
  • Resistor reduces radio frequency interference (RFI) and electrode erosion
See More

Autolite – Double Platinum Spark Plug: Platinum Firing, Superior Durability, Longer Life (Part No.APP3923)

Double Platinum Spark Plug: Platinum Firing, Superior Durability, Longer Life

from

$6.79
With over 100 years of engineering expertise and over 11 billion plugs sold, Autolite delivers exceptional quality. Designed and engineered in the USA, these spark plugs feature platinum-to-platinum firing, virtually eliminating gap erosion and reducing misfires. The OE design and full-platinum tips on both the center and side electrodes ensure reduced gap wear, while the platinum ball welding process provides a consistent point of contact for enhanced adhesion. This results in optimized engine performance, longer life, and improved fuel economy. The gasket seat type further enhances the plug’s reliability and durability.

Product Features:
  • Works to optimize engine performance for a longer life and improved fuel economy
  • OE design
  • Full-platinum tips; platinum on both the center and side electrodes to promote reduced gap wear
  • Platinum ball welding process provides a consistent point of contact for enhanced adhesion
  • Gasket Seat Type: Equipped with a gasket seat type that enhances the spark plug’s reliability and durability.
  • Proven Quality: Backed by over 100 years of engineering expertise and over 11 billion plugs sold, Autolite delivers exceptional quality and performance.
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DENSO – Iridium Power Spark Plug: Maximum Spark Energy, 0.4mm Iridium Tip, IKH20 (Part No.5344)

Iridium Power Spark Plug: Maximum Spark Energy, 0.4mm Iridium Tip, IKH20

from

$12.29
Increased performance with World’s smallest Iridium Center Eletrode (0.4mm).

Product Features:
  • World’s smallest Iridium Center Electrode (0.4mm) for improved spark for maximum combustion
  • Patented 360-degree laser welding assembly process
  • U-groove and taper cut ground electrode to maximize flame propagation.
  • Withstands temperatures greater than 4000┬░ Fahrenheit
  • Burnished nickel plating for high temperature endurance and superior corrosion resistance
  • Wide range of part numbers for thousands of applications, including classic and collector cars
  • Iridium Power
  • Superior Performance: This spark plug requires 5,000 less volts to fire compared to conventional spark plugs, providing maximum performance even under extreme conditions.
  • Enhanced Horsepower and Efficiency: Experience more horsepower, faster and easier starts, fewer misfires under heavy loads, and better fuel efficiency with the DENSO Iridium Power spark plug.
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NGK – OE Series Laser Iridium Spark Plug: Fine Wire Tip Design, ILFR6B (Part No.6481)

OE Series Laser Iridium Spark Plug: Fine Wire Tip Design, ILFR6B

from

$18.99
NGK Laser Iridium spark plugs offer the best combination of performance and longevity. Engineered specifically for OE applications, Laser Iridium spark plugs are tested to the highest standards to ensure quality and durability. Iridium tipped center electrode provides durability six times harder than platinum. NGKs high grade pure alumina ceramic and 98 percent pure copper core prevents the spark plug from overheating while providing reliable starts. Most Laser Iridium spark plugs feature a platinum pad on the ground electrode for even wear in distributorless ignition systems.

Product Features:
  • ACTUAL OE or EQUIVALENT DESIGN: OEM quality construction fine wire iridium alloy center electrode provides consistent performance
  • IRIDIUM ALLOY CENTER ELECTRODE: Iridium’s density (6x that of platinum) and extremely high melting point is perfect for modern high efficiency engines
  • PLATINUM TIP GROUND ELECTRODE: Unless OE specified, platinum protection at the ground electrode provides excellent ignitability and service life
  • SOLID COPPER CORE: 98% pure copper core offers superior heat dissipation, conductivity and ultra wide heat ranges
  • TRIVALENT METAL PLATING: Delivers superior anti-corrosion and anti-seizing properties, ensuring ease of installation and removal
  • RECOMMENDED USAGE: Best for vehicles with OE fine wire iridium alloy plugs
  • Superior Durability: The iridium-tipped center electrode is six times harder than platinum, ensuring long-lasting performance.
  • OE Application Specific: Engineered specifically for Original Equipment (OE) applications, ensuring a perfect fit and optimal performance.
  • Even Wear: Features a platinum pad on the ground electrode for even wear, particularly beneficial in distributorless ignition systems.
  • Fine Wire Tip Design: The fine wire tip design of the ILFR6B model enhances ignition efficiency and performance.
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DENSO – Platinum TT Spark Plug with Twin-Tip Design for Enhanced Ignition (Part No.4506)

Platinum TT Spark Plug with Twin-Tip Design for Enhanced Ignition

from

$5.99
This spark plug features a platinum twin-tip design and a titanium-enhanced ground strap, ensuring superior performance and longevity. The center electrode tip is made from high-quality platinum, providing excellent conductivity and durability. Additionally, the flat seat type ensures a secure and precise fit, making it an ideal choice for enhancing your vehicle’s ignition system.

Product Features:
  • Platinum Twin-Tip Design: The Denso Platinum TT Spark Plug features a twin-tip design with a high-quality platinum center electrode, ensuring excellent conductivity and enhanced ignition performance.
  • Titanium-Enhanced Ground Strap: Equipped with a titanium-enhanced ground strap, this spark plug offers superior durability and longevity, making it a reliable choice for your vehicle’s ignition system.
  • Superior Conductivity: The platinum center electrode tip provides excellent conductivity, ensuring efficient and consistent ignition for improved engine performance.
  • Enhanced Ignition System: Designed to enhance your vehicle’s ignition system, the Denso Platinum TT Spark Plug delivers superior performance and reliability, making it an ideal choice for automotive enthusiasts.
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DENSO – Platinum TT Spark Plug with Twin-Tip Design for Enhanced Ignition (Part No.4504)

Platinum TT Spark Plug with Twin-Tip Design for Enhanced Ignition

from

$3.99
This spark plug features a platinum twin-tip design and a titanium-enhanced ground strap, ensuring superior performance and longevity. The center electrode tip is made from high-quality platinum, providing excellent conductivity and durability. Additionally, the flat seat type ensures a secure and precise fit, making it an ideal choice for enhancing your vehicle’s ignition system.

Product Features:
  • Platinum Twin-Tip Design: Features a platinum twin-tip design for enhanced ignition performance and efficiency.
  • Titanium-Enhanced Ground Strap: Equipped with a titanium-enhanced ground strap, ensuring superior performance and longevity.
  • High-Quality Platinum Center Electrode: The center electrode tip is made from high-quality platinum, providing excellent conductivity and durability.
  • Superior Performance and Longevity: Designed to deliver superior performance and extended lifespan, making it a reliable choice for your vehicle’s ignition needs.
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E3 – DiamondFIRE Automotive Spark Plug: More Power, Saves Gas (Part No.E3.64)

DiamondFIRE Automotive Spark Plug: More Power, Saves Gas

from

$6.99
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. E3.64 is a 14mm, 0.750 reach plug with a gasket seat. It fits a wide variety of late model applications, especially import. E3.64 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.

Product Features:
  • E3’s Diamond Fire edge to edge ground electrode provides maximum performance with increased efficiency and a faster more complete burn
  • Smoother Acceleration & Idle – The faster flame initiated by the The spark plug results in a more complete burn of the ingested fuel charge. More pressure is created against the piston more fuel is put to work
  • Energy – Power output improved up to 6% on average in the typical operating ranges. Results will vary.
  • Efficiency – The “diamond shaped” side wire electrode projects the combustion spark in a way that more quickly ignites the air/fuel mixture, thereby creating a significantly faster and larger flame kernel. The result is that more fuel is put to work durin
  • E3’s patented Diamond Fire Technology provides a cleaner burning combustion, which translates into fuel savings and reduced engine carbon deposits
  • The Spark Plugs are pre-gapped at the factory and cannot be adjusted.
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Autolite Iridium – Iridium Ultra Finewire Spark Plug: Optimal Performance, Durability, Ignitability (Part No.AI5325)

Iridium Ultra Finewire Spark Plug: Optimal Performance, Durability, Ignitability

from

$10.99
Autolite Iridium Ultra Laser Finewire Spark Plugs are one of our brand’s most technologically advanced products. These spark plugs provide superior durability, more focused ignition with better overall ignitability for optimum performance. Autolite Spark Plugs are the best alternative to OE spark plugs, offering OE fit form and function supporting all foreign and domestic makes and models at a value price. Autolite provides the automotive aftermarket and original equipment manufacturers with the highest quality ignition products and is the leading supplier of spark plugs in the world.

Product Features:
  • Autolite Iridium Ultra is an engineered OE replacement iridium spark plug.
  • A laser-welded 0.5mm pure iridium finewire center electrode provides optimal fuel efficiency, acceleration and focused ignitability.
  • Nickel-plated shell to resist corrosion.
  • High-alumina ceramic insulator for increased strength.
  • Laser welded 0.5mm Iridium finewire center electrode.
  • Proprietary platinum sidewire technology.
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FAQs for 2004 Volvo S40 Spark Plugs

What are the most popular Spark Plugs for the 2004 Volvo S40?

With 6 brands you can trust, our most popular Spark Plugs for the 2004 Volvo S40 parts are:

What are the best aftermarket Spark Plugs for the 2004 Volvo S40?

See what past customers had to say about our highest-rated Spark Plugs for the 2004 Volvo S40:
DiamondFIRE Automotive Spark Plug: More Power, Saves Gas
from $6.99
(184)
DiamondFIRE Automotive Spark Plug: More Power, Saves Gas
“Great product”
Platinum TT Spark Plug with Twin-Tip Design for Enhanced Ignition
from $3.99
(105)
Platinum TT Spark Plug with Twin-Tip Design for Enhanced Ignition
“Very nice quality. Installed like factory. Ran great.”
Iridium Long-Life Spark Plug:  OE Performance, last 100K+ Miles, SK20HR11
from $11.49
(104)
Iridium Long-Life Spark Plug: OE Performance, last 100K+ Miles, SK20HR11
“Changed original plugs at 50k changed these at 77k. Great parts”