Denso 3471 Spark Plug

Denso Iridium Long Life Spark Plug 3471

The Denso Iridium Long Life spark plug 3471 is built for OE-level ignition performance, durability, and emissions control. It is a direct-fit spark plug for select Audi, Volkswagen, and Porsche applications, including Audi A8 Quattro, Audi S5, Audi A6 Quattro, Audi S6, Audi Q7, Audi S8, Volkswagen Touareg, and Porsche 911 models.

The Iridium Long Life line focuses on extended service life and stable spark delivery. This plug uses an iridium center electrode tip, a platinum chip ground electrode tip design, and a multi-electrode ground configuration to support consistent ignition under demanding operating conditions.

Key Features

• Brand: Denso Iridium Long Life
• Part number: 3471
• Iridium center electrode tip material for durable spark performance
• Platinum chip ground electrode tip design
• Multi-electrode ground configuration with 3 ground electrodes
• Copper center electrode core and nickel ground electrode core
• 5000 ohm resistance
• Pre-gap size: 1.1 mm
• Flat seat design, 14.00 mm thread diameter, 19.00 mm reach, 16.0 mm hex size
• Manufactured to OE performance, durability, and emissions standards

Detailed Description

Denso 3471 is an iridium spark plug engineered for select European performance and luxury vehicles that require precise ignition characteristics. The multi-electrode design and OE-style construction help maintain stable combustion, while the iridium tip supports long service intervals and reliable spark consistency. This part cross-references DENSO Auto Parts SK20BR11 for the same application.

Compatible With 2007-2012 Audi A8 Quattro, N/A; 2009-2012 Audi S5, N/A; 2007-2011 Audi A6 Quattro, N/A; 2007-2011 Audi S6, N/A; 2007-2010 Audi Q7, N/A; 2007-2009 Audi S8, N/A; 2007-2009 Volkswagen Touareg, N/A; and 2004-2005 Porsche 911, N/A. The Denso Iridium Long Life 3471 is also referenced by Volkswagen OE numbers 101 905 621 A, 101 905 621 B, and 101 905 640 A.

What It Helps Address

• Rough idle caused by worn spark plugs
• Hard starting from weak ignition output
• Misfire conditions related to plug wear or gap drift
• Reduced throttle response from inconsistent spark delivery
• Emissions issues tied to degraded ignition performance

Installation Notes and Tips

Verify thread diameter, reach, seat type, and heat range before installation. Confirm the specified gap and inspect ignition coils, boots, and wiring for wear before replacing plugs. Use the vehicle service specification for torque and installation procedure on Audi, Volkswagen, and Porsche applications.

Quality Assurance

Denso manufactures this spark plug to OE performance, durability, and emissions standards for the listed applications. The Iridium Long Life design is intended to deliver consistent ignition performance in demanding factory-fit applications.