Denso 3517 Spark Plug

Reliable Ignition Performance for Toyota Corolla and Prius Models

The Denso Iridium Long Life (SIP) spark plug, part number 3517, is engineered to provide consistent ignition performance for select Toyota vehicles. Designed specifically for models like the Corolla, Prius, Prius AWD-e, and Prius Prime, this spark plug supports efficient combustion and engine reliability.

• Iridium center electrode tip for enhanced durability
• Platinum needle ground electrode tip design
• Needle-to-needle ground configuration for precise spark delivery
• Copper center electrode core for optimal conductivity
• Flat seat type with 26.50 mm reach and 12.00 mm thread diameter
• Pre-gap size of 0.9 mm for accurate ignition timing
• Manufacturer heat range rating of 16
• Single ground electrode with nickel core material
• Hex size of 14.3 mm for standard installation tools
• Resistance value of 5000 ohms to reduce electrical noise

About the Denso Iridium Long Life (SIP) Product Line

The Iridium Long Life (SIP) line from Denso focuses on delivering extended service life and stable ignition performance. Utilizing iridium for the center electrode tip and platinum for the ground electrode tip, these spark plugs are designed to withstand high temperatures and resist wear. This combination supports improved fuel efficiency and reduced emissions, making it suitable for Toyota hybrid and conventional engines alike.

Technical Details and Application

The Denso 3517 spark plug features a copper core center electrode that enhances thermal conductivity, helping to dissipate heat effectively. The nickel core ground electrode with a platinum needle tip ensures precise spark generation and durability. The needle-to-needle ground configuration optimizes the spark gap, contributing to efficient combustion. With a pre-gap size of 0.9 mm and a flat seat design, this spark plug fits securely in the combustion chamber, maintaining consistent ignition timing.

Compatible Toyota Models and Common Issues Addressed

• Compatible with Toyota Corolla, Prius, Prius AWD-e, and Prius Prime models
• Helps resolve misfires and rough idling
• Improves cold start performance
• Reduces engine hesitation during acceleration
• Supports stable fuel combustion and emissions control

Installation Notes and Tips

When installing the Denso 3517 spark plug, ensure the correct torque is applied to avoid damage to the flat seat and threads. The 14.3 mm hex size allows for standard spark plug sockets. Verify the pre-gap size of 0.9 mm before installation, adjusting if necessary to match manufacturer specifications. Use anti-seize compound sparingly on the threads to prevent galling, especially in aluminum cylinder heads.

Quality Assurance and Warranty

Denso spark plugs undergo rigorous testing to meet OEM standards for fit, form, and function. The Iridium Long Life (SIP) spark plug is manufactured with high-quality materials to ensure durability and consistent performance. While specific warranty details may vary, Denso products typically come with a limited warranty covering defects in materials and workmanship.