Denso 3137 Spark Plug

Denso 3137 U-Groove Spark Plug Overview

Denso 3137 is a conventional spark plug built for direct-fit ignition service in a wide range of BMW, Mercedes-Benz, Saab, and Jaguar applications. Its U-groove electrode design is engineered to improve ignitability, helping support smoother combustion and consistent engine efficiency.

The Denso U-Groove Conventional line focuses on dependable secondary ignition performance with OE-style fitment and materials selected for stable spark delivery.

Key Features

• U-groove ground electrode design for improved spark exposure
• 5000 ohm resistor for ignition noise suppression
• Copper center electrode core for efficient heat transfer
• Nickel center and ground electrode tip materials
• Standard ground configuration with a flat seat
• 14.00 mm thread diameter, 19.00 mm reach, 16.0 mm hex size
• Pre-gapped to 0.8 mm
• Manufacturer heat range 16

Detailed Product Description

This Denso 3137 spark plug uses a U-groove ground electrode to expose the spark kernel more effectively than a conventional flat design. The result is a plug built for reliable ignition performance in engines that call for a flat-seat, 14 mm spark plug with a 19.00 mm reach. With a copper core center electrode and nickel electrode tips, it is designed for stable heat control and consistent firing characteristics in secondary ignition systems.

Fits 1999 Jaguar XK8, N/A. Fits 1997 Mercedes-Benz C280, N/A. Fits 1997 Mercedes-Benz E420, N/A. Fits 1994-1995 Mercedes-Benz E420, N/A. Fits 1997 Mercedes-Benz S420, N/A. Fits 1994-1995 Mercedes-Benz S420, N/A. Fits 1997 Mercedes-Benz S500, N/A. Fits 1994-1995 Mercedes-Benz S500, N/A. Fits 1997 Mercedes-Benz SL320, N/A. Fits 1997 Mercedes-Benz SL500, N/A. Fits 1994-1995 Mercedes-Benz SL500, N/A. Fits 1994-1996 Mercedes-Benz C220, N/A. Fits 1994-1995 BMW 850CSi, N/A. Fits 1994-1995 Mercedes-Benz E320, N/A. Fits 1994-1995 Mercedes-Benz S600, N/A. Fits 1994-1995 Mercedes-Benz SL600, N/A. Fits 1988-1994 BMW 750iL, N/A. Fits 1993-1994 BMW 850Ci, N/A. Fits 1994 Mercedes-Benz E500, N/A. Fits 1992-1993 Mercedes-Benz 300CE, N/A. Fits 1990 Mercedes-Benz 300CE, N/A. Fits 1993 Mercedes-Benz 300E, N/A. Fits 1992-1993 Mercedes-Benz 300SE, N/A. Fits 1990-1993 Mercedes-Benz 300SL, N/A. Fits 1993 Mercedes-Benz 300TE, N/A. Fits 1992-1993 Mercedes-Benz 400E, N/A. Fits 1993 Mercedes-Benz 400SEL, N/A. Fits 1992-1993 Mercedes-Benz 500E, N/A. Fits 1993 Mercedes-Benz 500SEC, N/A. Fits 1992-1993 Mercedes-Benz 500SEL, N/A. Fits 1990-1993 Mercedes-Benz 500SL, N/A. Fits 1993 Mercedes-Benz 600SEC, N/A. Fits 1992-1993 Mercedes-Benz 600SEL, N/A. Fits 1993 Mercedes-Benz 600SL, N/A. Fits 1991-1993 Saab 900, N/A. Fits 1991-1992 BMW 850i, N/A. Fits 1992 Mercedes-Benz 400SE, N/A. Fits 1989-1990 Saab 9000, N/A.

This part cross-references DENSO Auto Parts Q16PR-U and Mercedes-Benz 003 159 42 03 for the same application.

Common Issues This Spark Plug Addresses

• Hard starting caused by worn or fouled spark plugs
• Rough idle from weak or inconsistent spark delivery
• Misfire conditions related to aged secondary ignition components
• Reduced combustion efficiency from excessive electrode wear
• Ignition noise concerns in resistor-equipped systems

Installation Notes and Tips

Verify thread diameter, reach, seat type, and heat range against the vehicle’s original specification before installation. The plug is pre-gapped to 0.8 mm, but gap verification is still recommended during service. Use the correct 16.0 mm spark plug socket and follow the manufacturer’s torque specification for the engine being serviced.

Quality Assurance

Denso manufactures this U-Groove Conventional spark plug to OE-style dimensional and material standards for direct replacement use in listed applications. Part number 3137 is built for consistent fitment and ignition performance across the confirmed vehicle coverage.