Denso 3122 Spark Plug

Denso 3122 U-Groove Spark Plug Overview

Denso 3122 is a conventional spark plug built for stable ignition performance across a wide range of import applications. Its U-Groove ground electrode design helps improve ignitability for more efficient combustion, while the copper core and nickel electrode materials support consistent spark delivery.

Compatible With Mercedes-Benz CL600, SL600, CL65 AMG, SL65 AMG, and S600 applications, as well as select Toyota, Lexus, Nissan, and Mitsubishi models, this Denso U-Groove Conventional spark plug is a direct-fit service part for many OE-style ignition systems.

Key Features

• U-Groove ground electrode tip design for improved ignitability
• Conventional spark plug construction for everyday service replacement
• Copper center electrode core material for dependable heat transfer
• Nickel center and ground electrode tip materials for consistent wear characteristics
• 5000 ohm resistance for suppression of electrical noise
• 0.8 pre-gap size, 14.00 mm thread diameter, 19.00 mm reach, and flat seat type
• Fits a broad range of import vehicles, including Mercedes-Benz, Toyota, Lexus, Nissan, and Mitsubishi

Product Details

The Denso U-Groove Conventional line focuses on practical ignition performance with a design that promotes better spark exposure at the plug gap. On this Denso 3122 spark plug, the U-shaped ground electrode helps the flame kernel form more efficiently, which can support smoother combustion and reliable engine operation in properly matched applications. This part cross-references DENSO Auto Parts K20R-U for the same application.

Vehicle coverage includes Fits 2003-2006 Mercedes-Benz CL600, N/A; Fits 2008-2009 Mercedes-Benz CL600, N/A; Fits 2011-2014 Mercedes-Benz CL600, N/A; Fits 2005-2006 Mercedes-Benz CL65 AMG, N/A; Fits 2008-2014 Mercedes-Benz CL65 AMG, N/A; Fits 2005-2009 Mercedes-Benz SL600, N/A; Fits 2003-2013 Mercedes-Benz S600, N/A; Fits 2006-2013 Mercedes-Benz S65 AMG, N/A; Fits 2003-2006 Mitsubishi Montero, N/A; Fits 2001-2004 Toyota Sequoia, N/A; Fits 2000-2004 Toyota Tundra, N/A; Fits 1995-1996 Lexus LS400, N/A; Fits 1993-1998 Nissan Quest, N/A; Fits 1991-1995 Toyota MR2, N/A; Fits 1990-1993 Toyota Celica, N/A; and Fits 1990-1991 Toyota Corolla, N/A.

Common Uses

• Replacing worn spark plugs that cause rough idle
• Addressing hard starting or inconsistent ignition performance
• Restoring combustion efficiency in high-mileage tune-ups
• Correcting misfire-related drivability concerns when the plug is the source
• Servicing OE-style ignition maintenance on select Mercedes-Benz, Toyota, Lexus, Nissan, and Mitsubishi models

Installation Notes

Verify thread diameter, reach, seat type, and pre-gap before installation. The listed fitment includes applications where two spark plugs are required per cylinder on certain Mercedes-Benz models, so confirm the engine configuration and service procedure before ordering. Use the vehicle’s specified torque and ignition service guidelines, and inspect coil boots and plug wells during replacement.

Quality Assurance

Denso is known for OE-level ignition component engineering, and the 3122 uses a conventional nickel-and-copper construction with a U-Groove electrode layout for consistent service replacement performance. Part number 3122 is also referenced by Toyota 90919-01166 and Datsun/Nissan 22401-0B016, 22401-53J06 for select applications.