Denso 5391 Spark Plug

Overview of Denso Iridium Power Spark Plug 5391

The Denso Iridium Power 5391 spark plug is engineered for reliable ignition performance and enhanced durability. Designed with advanced materials and precise specifications, it supports efficient combustion in various vehicle applications, including popular makes and models requiring a 14mm thread diameter and 19mm reach.

• Iridium center electrode tip for improved ignition and longevity
• Tapercut U-groove ground electrode tip design for better spark exposure
• Copper core center electrode for optimal conductivity
• Nickel ground electrode core material with standard ground configuration
• Flat seat type with 0.8mm pre-gap size for consistent spark gap
• Hex size of 20.6mm for easy installation
• Manufacturer heat range of 24 suitable for moderate engine temperatures
• Resistance rating of 5000 ohms to reduce electrical noise interference

Detailed Product Features and Specifications

The Denso Iridium Power 5391 spark plug features a single ground electrode with a tapercut U-groove tip design, which enhances spark exposure and combustion efficiency. The center electrode is constructed with a copper core for excellent thermal conductivity, topped with an iridium tip that provides durability and consistent ignition performance. The ground electrode is made from nickel, offering reliable wear resistance. This spark plug has a flat seat type and a pre-gap size of 0.8mm, ensuring a precise spark gap for optimal engine operation. With a thread diameter of 14mm and a reach of 19mm, it fits a range of vehicles requiring these dimensions. The resistance of 5000 ohms helps minimize radio frequency interference, supporting stable engine electronics.

About the Iridium Power Product Line

The Denso Iridium Power line is designed to deliver enhanced ignition performance through the use of iridium-tipped electrodes. This product line focuses on improving throttle response and fuel efficiency while maintaining long service life. The 5391 spark plug exemplifies these qualities by combining iridium technology with a copper core center electrode and a specialized ground electrode design, making it suitable for drivers seeking reliable secondary ignition components.

Applications and Common Issues Addressed

• Replacement for worn or fouled spark plugs causing misfires
• Improves ignition stability in vehicles experiencing rough idling
• Helps restore fuel efficiency in engines with inconsistent combustion
• Reduces radio frequency interference affecting vehicle electronics
• Supports consistent engine performance in moderate heat range applications

Installation Notes and Tips

Ensure the spark plug gap is set to the manufacturer’s recommended specification before installation, although the pre-gap is set at 0.8mm. Use a torque wrench to tighten the spark plug to the vehicle manufacturer’s torque specification to avoid damage to the threads or seat. The 20.6mm hex size allows for standard spark plug socket compatibility. Verify compatibility with your vehicle’s make and model, especially those requiring a 14mm thread diameter and 19mm reach.

Quality Assurance and Warranty

Denso manufactures the Iridium Power 5391 spark plug to meet strict quality standards, ensuring consistent performance and durability. While specific warranty details vary by distributor, Denso products typically come with a limited warranty covering defects in materials and workmanship. Consult your parts provider for exact warranty terms related to this spark plug.