Bosch 9621 Spark Plug

Overview of Bosch OE Fine Wire Double Iridium Spark Plug 9621

The Bosch OE Fine Wire Double Iridium Spark Plug 9621 is engineered for reliable ignition performance in select INFINITI, Mazda, Nissan, Pontiac, Scion, and Toyota vehicles. Designed with advanced materials and precise specifications, this spark plug supports efficient combustion and consistent engine operation.

• Double iridium center and ground electrode tips for enhanced durability
• Tapered ground electrode tip design for improved spark exposure
• Resistance value of 6000 ohms to reduce electrical interference
• Flat seat type with a 14mm hex size for secure installation
• Pre-gap size of 1.1 mm optimized for 4-cycle engines
• Thread diameter of 12 mm and reach of 26.5 mm for proper fitment
• Ceramic insulator material with non-projected insulator type
• Manufacturer heat range rating of 7 for balanced thermal performance

Detailed Product Description and Attributes

The Bosch OE Fine Wire Double Iridium spark plug 9621 features a center electrode tip made of iridium, known for its high melting point and wear resistance, paired with a ground electrode tip composed of platinum-iridium and nickel-yttrium. This combination ensures long service life and stable spark generation. The tapered ground electrode tip design enhances spark exposure to the air-fuel mixture, promoting efficient combustion. The spark plug includes a resistor with a resistance of 6000 ohms to minimize radio frequency interference, protecting vehicle electronics.

With a flat seat type and a 14 mm hex size, the spark plug is designed for straightforward installation and secure fitment. The thread diameter of 12 mm and reach of 26.5 mm align with OEM specifications for compatible vehicles. The ceramic insulator provides excellent electrical insulation and heat resistance, while the non-projected insulator type supports consistent spark gap maintenance. The manufacturer heat range of 7 balances heat dissipation and prevents fouling in typical operating conditions.

About the OE Fine Wire Double Iridium Product Line

The OE Fine Wire Double Iridium line from Bosch focuses on delivering spark plugs with fine wire electrodes made from iridium and platinum alloys. This design reduces electrode wear and improves ignition reliability compared to conventional plugs. The double iridium construction enhances durability and maintains optimal spark performance over extended service intervals, making it suitable for modern 4-cycle engines found in many INFINITI, Mazda, Nissan, Pontiac, Scion, and Toyota models.

Compatible Vehicles and Common Applications

• INFINITI models such as Q50, Q60, Q70, and QX series
• Mazda vehicles including CX-3, CX-5, CX-30, CX-50, CX-70, CX-90, and MX-5 Miata
• Nissan models like Altima, Frontier, Murano, Pathfinder, Rogue, Sentra, TITAN, and TITAN XD
• Pontiac and Scion models where applicable
• Toyota vehicles including Corolla, Yaris, and Yaris iA

Common Issues Addressed by Bosch Spark Plug 9621

• Misfiring or rough idling due to worn or fouled spark plugs
• Reduced fuel efficiency from incomplete combustion
• Difficulty starting the engine in cold or damp conditions
• Engine hesitation or loss of power under acceleration
• Excessive emissions caused by inefficient ignition

Installation Notes and Tips

• Verify compatibility with your vehicle’s make and model before installation
• Use a torque wrench to tighten the spark plug to manufacturer specifications to avoid damage
• Check and adjust the spark plug gap if necessary; the pre-gap size is 1.1 mm
• Inspect the ignition coil and wiring for wear or damage during replacement
• Replace spark plugs in sets to maintain balanced engine performance

Quality Assurance and Warranty

Bosch OE Fine Wire Double Iridium spark plugs are manufactured to meet strict OEM standards, ensuring consistent quality and performance. The use of premium materials such as iridium and platinum alloys contributes to extended service life and reliable ignition. While specific warranty details may vary, Bosch typically offers coverage against manufacturing defects. Consult your vehicle’s service manual or Bosch documentation for warranty information related to part number 9621.