Denso 4103 Spark Plug

Denso 4103 U-Groove Spark Plug Overview

Denso 4103 is a conventional spark plug built for reliable secondary ignition performance with a U-groove ground electrode design. The copper core center electrode, nickel tip materials, and 0.7 pre-gap support consistent spark delivery for drivers looking for a direct-fit ignition service part.

Compatible With applications that call for Denso X24FS-U, this spark plug is a practical choice for routine tune-up service on vehicles such as Honda Civic and Toyota Corolla applications where the specified thread diameter, reach, and seat type match the engine requirements.

Key Features

• U-groove ground electrode tip design for improved ignitability
• Copper core center electrode for stable heat transfer
• Nickel center and ground electrode tip materials
• Standard ground configuration with one ground electrode
• 0.7 pre-gap size for specified ignition setup
• 12.00 mm thread diameter, 12.70 mm reach, and flat seat type
• 18.0 mm hex size for proper service-tool fit
• Manufacturer heat range 24

Product Details

The Denso U-Groove Conventional line focuses on dependable ignition performance in a straightforward spark plug design. Part number 4103 uses a U-shaped ground electrode profile to improve spark exposure at the gap, which supports cleaner ignition events and more efficient combustion when the engine calls for this plug specification. The Denso 4103 cross-references DENSO Auto Parts X24FS-U for the same application.

Common Issues This Spark Plug Can Address

• Hard starting caused by worn or fouled spark plugs
• Rough idle from inconsistent spark delivery
• Misfire symptoms tied to excessive electrode wear
• Reduced throttle response from weak ignition performance
• Service intervals due for routine ignition maintenance

Installation Notes

Verify the engine’s required thread diameter, reach, seat type, and heat range before installation. Use the specified gap setting for the application and confirm the plug seats correctly in the cylinder head. For Honda Civic and Toyota Corolla service, match the OE-style plug specification exactly to avoid drivability issues.

Quality Assurance

Denso manufactures ignition components with application-specific engineering and consistent dimensional control. Part number 4103 is built as a conventional replacement spark plug for engines that specify this Denso design and heat range.