Denso 3509 Spark Plug

Reliable Ignition Performance for Toyota Tacoma

The Denso Iridium Long Life (SIP) spark plug, part number 3509, is engineered to provide consistent ignition and enhanced durability for your Toyota Tacoma. Designed with advanced materials and precise specifications, this spark plug supports efficient combustion and long-term engine reliability.

• Iridium center electrode tip for improved ignition and wear resistance
• Platinum needle ground electrode tip with needle-to-needle configuration
• Copper core center electrode for optimal conductivity
• Flat seat type with 14.00 mm thread diameter and 26.50 mm reach
• Pre-gap size of 0.8 mm for precise spark delivery
• Hex size of 16.0 mm for standard installation tools
• Manufacturer heat range rating of 20 for balanced thermal performance

About the Iridium Long Life (SIP) Product Line

The Iridium Long Life (SIP) line from Denso focuses on delivering extended service life and stable ignition performance through the use of iridium and platinum electrode materials. This product line is designed to withstand high temperatures and resist electrode wear, making it suitable for vehicles like the Toyota Tacoma that require reliable secondary ignition components.

Technical Details and Features

The Denso 3509 spark plug features a copper core center electrode with an iridium tip, which enhances electrical conductivity and durability. The ground electrode uses a platinum needle tip in a needle-to-needle configuration, improving spark precision and reducing misfires. The nickel core material in the ground electrode adds strength and heat resistance. With a flat seat and a thread diameter of 14.00 mm, this spark plug fits securely in the combustion chamber. The 0.8 mm pre-gap size is optimized for efficient ignition, while the 16.0 mm hex size allows for easy installation using common tools.

Compatible Applications and Common Issues Addressed

• Compatible with Toyota Tacoma models requiring a 14 mm thread diameter spark plug
• Helps resolve engine misfires and rough idling caused by worn spark plugs
• Improves cold start performance and throttle response
• Reduces electrode wear for longer service intervals
• Supports stable combustion to lower emissions and improve fuel efficiency

Installation Notes and Tips

Ensure the spark plug gap is set to 0.8 mm before installation if not pre-gapped. Use a torque wrench to tighten the spark plug to the manufacturer’s recommended specifications to avoid damage to the threads or combustion chamber. The 16.0 mm hex size is compatible with standard spark plug sockets. Inspect the spark plug seat type to confirm compatibility with your Toyota Tacoma’s cylinder head.

Quality Assurance and Warranty

Denso spark plugs, including part number 3509, are manufactured to meet strict quality standards for durability and performance. The use of iridium and platinum materials ensures resistance to electrode erosion and consistent ignition over time. While specific warranty details may vary, Denso products typically come with manufacturer-backed quality assurance to support reliable operation in secondary ignition systems.