Denso 4037 Spark Plug

Denso 4037 Spark Plug Overview

The Denso 4037 is a conventional spark plug built to OEM quality standards for dependable secondary ignition performance. It uses a copper core center electrode with a nickel tip and a nickel ground electrode to support consistent spark delivery in everyday driving.

For drivers searching for a Denso spark plug for Honda Civic or other OE-style ignition service, this part number 4037 offers a straightforward replacement option with a 0.7 pre-gap and a 5000 ohm resistor for radio noise suppression.

Key Features

• Brand: Denso U-Groove Conventional spark plug
• Part number: 4037
• Manufactured to OEM quality standards
• Copper center electrode core with nickel tip material
• Nickel ground electrode core material and standard ground configuration
• 5000 ohm resistance for secondary ignition applications
• 0.7 pre-gap size for OE-style setup
• 14.00 mm thread diameter, 12.70 mm reach, and flat seat type
• 20.6 mm hex size for proper socket fitment
• Manufacturer heat range: 24

Product Details

The Denso U-Groove Conventional line focuses on practical ignition service with a standard electrode layout and OE-oriented dimensions. The U-Groove design supports stable spark exposure, while the copper core helps manage heat transfer in normal engine operation. This Denso 4037 spark plug is a direct-fit style service part for applications that call for the listed thread, reach, seat, and gap specifications.

This part cross-references DENSO Auto Parts (e.g., W24FSR) for the same application.

Common Issues This Part Can Address

• Hard starting caused by worn or fouled spark plugs
• Rough idle from weak or inconsistent ignition output
• Misfire symptoms related to aged secondary ignition components
• Reduced fuel economy from degraded spark performance
• Engine hesitation during acceleration under load

Installation Notes and Tips

Verify thread diameter, reach, seat type, and heat range before installation. Check the gap against the engine specification before fitting, even when the plug is pre-gapped. Use the correct 20.6 mm spark plug socket and tighten to the vehicle manufacturer’s torque specification. For Honda Civic spark plug service or other OE-style ignition maintenance, inspect plug wires or coil-on-plug components at the same time.

Quality Assurance

Denso manufactures this spark plug to OEM quality standards for consistent fit and service performance. The 4037 part number is built for standard ignition maintenance where OE-style dimensions and materials matter.