Bosch 96318 Spark Plug

Bosch OE Fine Wire Double Iridium Spark Plug

Bosch 96318 is an OE Fine Wire Double Iridium spark plug built for direct replacement service in select Subaru applications. It combines an ultra-fine wire center electrode with a laser-welded ground electrode to support consistent ignition performance and long service life.

This Bosch OE Fine Wire Double Iridium line focuses on OE-style fit and durable electrode construction. For Subaru WRX STI, Subaru WRX, and Subaru Forester applications, the preset gap and 12 mm thread diameter help match the original plug specification without adjustment.

Key Features

• Fine-wire double iridium design for strong ignitability and extended wear resistance
• Laser-welded ground electrode with iridium alloy inlay
• Iridium center electrode firing pin for stable spark delivery
• Preset gap; do not gap before installation
• Resistor plug with 6000 resistance rating
• Projected ceramic insulator and flat seat design
• 12 mm thread diameter, 14 mm hex size, 26.5 mm reach

Detailed Description

Bosch 96318 is engineered as an OE-style spark plug for modern 4-cycle ignition systems that require precise electrode geometry and long-term durability. The fine-wire iridium center electrode and laser-welded ground electrode help maintain consistent spark characteristics under demanding driving conditions. This part number 96318 is listed for 2020 Subaru WRX STI, 2019 Subaru WRX, 2015-2017 Subaru WRX, and 2014-2018 Subaru Forester applications. It is also identified as previously cataloged under 9689.

For drivers searching for a Subaru WRX spark plug, Subaru WRX STI spark plug, or Subaru Forester iridium spark plug, Bosch OE Fine Wire Double Iridium provides the OE-style construction expected in direct replacement service. The plug uses a ceramic insulator, standard ground configuration, and preset .6 gap to match the original specification.

Common Issues This Part Addresses

• Rough idle caused by worn spark plug electrodes
• Hard starting from weakened ignition output
• Misfire conditions related to plug wear or inconsistent spark
• Reduced throttle response from degraded ignition performance
• Service intervals shortened by conventional plug wear

Installation Notes and Tips

Install Bosch 96318 only in the Subaru WRX STI, WRX, and Forester applications listed above. The gap is preset, so do not gap the plug before installation. Verify the engine calls for a 12 mm thread diameter, 26.5 mm reach, flat seat, and heat range 6 before service. Use proper spark plug removal and torque procedures to protect the cylinder head and ignition components.

Quality Assurance

Bosch OE Fine Wire Double Iridium plugs are built with iridium-alloy electrode materials and laser-welded construction to support durable OE replacement performance. Part number 96318 is designed around the original plug specification for the listed Subaru applications.