Denso 4028 Spark Plug

Denso 4028 Spark Plug Overview

The Denso 4028 spark plug is a conventional ignition component built for reliable secondary ignition performance. Its U-groove ground electrode design helps improve ignitability, supporting more efficient combustion in the right application.

For drivers searching for a Denso spark plug for Honda Civic or other import ignition service, this part number 4028 combines a copper core center electrode with nickel electrode materials and a standard ground configuration.

Key Features

• U-groove ground electrode tip design for improved spark exposure
• Copper core center electrode for stable heat transfer
• Nickel center and ground electrode tip materials
• Pre-gapped to 0.8 mm
• 14.00 mm thread diameter with flat seat type
• 19.00 mm reach and 20.6 mm hex size
• Manufacturer heat range 24

Product Details

Denso U-Groove Conventional spark plugs are engineered as straightforward OE-style ignition service parts. The U-shaped ground electrode helps the spark find a more direct path across the gap, which can improve ignitability in engines that call for this specification. The Denso 4028 is built with a nickel ground electrode, nickel-tipped center electrode, and copper core center electrode to support consistent electrical performance and heat dissipation.

This spark plug is a direct-fit style component for applications that specify a 14.00 mm thread diameter, 19.00 mm reach, flat seat, and 0.8 mm pre-gap. If you are replacing worn plugs in a Honda Civic or checking a Denso 4028 replacement for import ignition maintenance, verify the engine’s required heat range and dimensions before installation.

This part cross-references DENSO Auto Parts (e.g., W24EP-U) for the same application.

Common Issues This Part Can Address

• Hard starting caused by worn or fouled spark plugs
• Rough idle from inconsistent ignition firing
• Misfire conditions related to electrode wear
• Reduced fuel efficiency from weak spark delivery
• Loss of throttle response from degraded secondary ignition performance

Installation Notes and Tips

Confirm the engine calls for a 14.00 mm thread diameter, 19.00 mm reach, flat seat, and 0.8 mm gap before installation. Inspect the plug wells, threads, and ignition components during service, and torque the plug to the vehicle manufacturer’s specification. For Honda Civic spark plug replacement or other Denso 4028 fitment searches, always match the heat range and seat style to the engine requirements.

Quality Assurance

Denso’s U-Groove Conventional line focuses on practical ignition performance with OE-style construction and application-specific dimensions. Part number 4028 is built to the listed specifications for accurate fitment in the correct engine application.