Denso 3370 Spark Plug

Denso Iridium Long Life Spark Plug 3370

Denso Iridium Long Life spark plug 3370 is built for precise ignition performance in secondary ignition systems. It uses an iridium center electrode, a platinum chip ground tip, and OE-focused construction to support stable combustion, consistent firing, and long service life.

The Iridium Long Life line is Denso’s OE-oriented spark plug family, engineered to meet strict factory standards for performance, durability, and emissions control. For drivers searching for a Denso 3370 spark plug for Dodge Avenger, BMW 750iL, BMW 850Ci, or Mazda Millenia applications, this plug is built around the specifications that matter most in daily operation.

Key Features

• Iridium center electrode tip material for durable spark delivery
• Platinum chip ground electrode tip design for stable ignition performance
• Copper center electrode core and nickel ground electrode core
• 0.8 pre-gap size for OE-style setup
• 5000 resistance specification for ignition system compatibility
• Flat seat design, 14.00 mm thread diameter, and 19.00 mm reach
• Manufacturer heat range 16
• Compatible With 2008-2014 Dodge Avenger, N/A
• Compatible With 1995-1998 BMW 750iL, N/A
• Compatible With 1995-1997 BMW 850Ci, N/A
• Compatible With 1998 Mazda Millenia, N/A

Detailed Description

Denso spark plug 3370 is designed for vehicles that require an OE-style secondary ignition component with iridium firing durability and a platinum chip ground design. The combination of iridium at the center electrode and a copper-core construction helps maintain consistent ignition characteristics, while the flat seat and specified reach support proper cylinder head fitment. This makes it a direct-fit option for select Dodge Avenger, BMW 750iL, BMW 850Ci, and Mazda Millenia applications listed in the fitment data.

This part cross-references DENSO Auto Parts SKJ16CR-A8 and Mazda ZM01-18-110 for the same application.

What It Helps Address

• Rough idle caused by worn spark plug electrodes
• Hard starting from weak or inconsistent spark output
• Misfire conditions related to aged ignition components
• Reduced fuel economy from incomplete combustion
• Loss of throttle response from degraded plug performance

Installation Notes and Tips

Verify the thread diameter, reach, seat type, and heat range against the original plug before installation. Confirm the pre-gap specification and inspect ignition coils, boots, and wires for wear so the new plug can operate within the intended ignition system setup. Use the vehicle service procedure for torque and gap verification.

Quality Assurance

Denso manufactures this spark plug to OE performance, durability, and emissions standards. The Iridium Long Life design reflects Denso’s factory-focused approach to ignition components for select BMW, Dodge, and Mazda applications.