Denso 4176 Spark Plug

Denso 4176 U-Groove Spark Plug Overview

Denso 4176 is a conventional spark plug built around a U-Groove ground electrode design for improved ignitability and more consistent combustion. It uses a copper center electrode core with nickel tip materials and a 5,000 ohm resistor for stable secondary ignition performance.

For drivers searching for a Denso spark plug for Honda Civic, Toyota Corolla, or similar import applications, this part number 4176 is a direct-fit style ignition service component where the specified thread, reach, seat, and gap dimensions match the engine’s requirements.

Key Features

• U-Groove ground electrode design for improved spark exposure
• Conventional spark plug construction for standard ignition service
• 5000 ohm resistor for electrical noise suppression
• Copper center electrode core for efficient heat transfer
• Nickel center and ground electrode tip materials
• Pre-gapped to 0.8 mm
• 14.00 mm thread diameter, 19.00 mm reach, flat seat
• 20.6 mm hex size and manufacturer heat range 31

Product Details

The Denso U-Groove Conventional line focuses on dependable secondary ignition performance with a ground electrode shape that helps expose the spark kernel more effectively than a standard flat design. On part number 4176, the nickel-tipped U-groove ground electrode works with the copper-core center electrode to support efficient ignition under normal operating conditions. This makes it a practical choice for routine spark plug replacement on vehicles such as Honda Civic and Toyota Corolla applications that call for this specification.

This part cross-references DENSO Auto Parts (e.g., W31ESR-U) for the same application.

What This Spark Plug Helps Address

• Hard starting caused by worn or fouled spark plugs
• Rough idle from weak or inconsistent spark delivery
• Misfire conditions related to degraded secondary ignition components
• Reduced fuel efficiency from incomplete combustion
• Loss of throttle response from aging ignition service parts

Installation Notes and Tips

Verify the engine calls for a 14.00 mm thread diameter, 19.00 mm reach, flat seat, and 0.8 mm pre-gap before installation. Check the existing plug specification against the vehicle service information, especially when servicing Honda Civic or Toyota Corolla ignition systems. Use proper torque procedures and inspect the ignition coil, wires, and plug wells during replacement to avoid repeat misfire concerns.

Quality Assurance

Denso manufactures this spark plug as part of its U-Groove Conventional product line, which is built around a specific electrode geometry and material set for consistent ignition service. Part number 4176 is engineered to meet the listed electrical and dimensional specifications for the intended application.