Denso 3403 Spark Plug

Reliable Ignition Performance for Select Vehicle Models

The Denso Iridium Long Life 3403 spark plug is engineered to provide consistent ignition and durability for a wide range of vehicles including Audi A4, Toyota Corolla, and Volkswagen Golf. Designed with advanced materials, this spark plug supports efficient combustion and long-term engine performance.

• Iridium center electrode tip for enhanced durability and ignition
• Platinum chip ground electrode tip for stable spark and wear resistance
• Copper core center electrode for improved conductivity
• Standard ground configuration with nickel core ground electrode
• Pre-gap size of 0.8 mm for optimal spark gap
• Flat seat type with 14 mm thread diameter and 19 mm reach
• Hex size of 16 mm for easy installation
• Manufacturer heat range rating of 20
• Resistance of 5000 ohms to reduce electrical noise

About the Denso Iridium Long Life Spark Plug Line

The Iridium Long Life series by Denso is designed to offer extended service life and reliable ignition performance. Featuring iridium and platinum materials on the electrode tips, these spark plugs maintain stable combustion over time, reducing the need for frequent replacements. The 3403 part number is part of this line, combining advanced electrode materials with precise engineering to meet the demands of various vehicle makes and models.

Technical Details and Compatibility

This spark plug features a copper core center electrode with an iridium tip, which enhances electrical conductivity and durability. The ground electrode uses a platinum chip tip and nickel core, providing wear resistance and consistent spark delivery. With a pre-gap size of 0.8 mm and a flat seat design, it ensures proper fit and ignition efficiency. The 14 mm thread diameter and 19 mm reach make it compatible with many vehicles including Audi A4 Quattro, Toyota Corolla, Volkswagen GTI, and Nissan models.

Common Applications and Problem Solving

• Improves engine misfire issues in compatible Audi, Toyota, and Volkswagen vehicles
• Reduces rough idling and hesitation during acceleration
• Enhances fuel efficiency by ensuring complete combustion
• Minimizes spark plug fouling and wear over time
• Supports stable ignition in vehicles with secondary ignition systems

Installation Notes and Tips

When installing the Denso 3403 spark plug, ensure the pre-gap is set to 0.8 mm if adjustment is necessary. Use a 16 mm socket wrench for proper torque application. The flat seat design requires careful seating to avoid damage to the cylinder head. It is recommended to replace spark plugs in sets to maintain balanced engine performance. Always consult the vehicle’s service manual for specific installation procedures and torque specifications.

Quality Assurance and Warranty

Denso spark plugs are manufactured to meet strict quality standards, ensuring reliable performance and durability. The Iridium Long Life 3403 spark plug undergoes rigorous testing for heat range, resistance, and electrode integrity. While specific warranty details may vary, Denso products typically come with manufacturer-backed quality assurance to support long-term use in compatible vehicles.