Denso 5008 Spark Plug

Denso 5008 U-Groove Spark Plug Overview

The Denso 5008 is a conventional spark plug built for older Ford, Mercury, and Lincoln applications that call for an 18 mm, tapered-seat plug with a 0.9 pre-gap. Its U-Groove ground electrode design is engineered to improve ignitability, helping support more efficient combustion in the engine.

For drivers servicing classic Ford F-150, F-250, Bronco, and related V8 applications, this Denso spark plug offers a straightforward OE-style replacement with the specifications needed for proper fitment and consistent ignition performance.

Key Features

• Part number: Denso 5008
• U-Groove ground electrode tip design for improved spark exposure
• Conventional spark plug construction for older ignition systems
• 5000 ohm resistor for noise suppression
• Copper center electrode core material for stable conductivity
• Nickel center and ground electrode tip materials
• 0.9 pre-gap size
• 18.00 mm thread diameter with tapered seat
• 20.6 mm hex size
• Manufacturer heat range: 16

Product Details

The Denso U-Groove Conventional line focuses on practical ignition performance for vehicles that were originally designed around traditional spark plug technology. The U-shaped ground electrode helps expose more of the air-fuel mixture to the spark kernel, which can support cleaner, more consistent ignition in the right application. The Denso 5008 is built with a copper core center electrode, nickel electrode materials, and a resistor design that helps reduce electrical interference in the ignition system.

This spark plug is listed for a wide range of Ford F-150, Ford F-250, Ford F-350, Ford Bronco, and Ford E-Series applications, along with select Mercury and Lincoln models. If you are servicing a 1965-1995 Ford F-150 or a 1958-1972 Lincoln Continental, the Denso 5008 provides the correct conventional plug format for those engine families.

This part cross-references DENSO Auto Parts (e.g., MA16PR-U) for the same application.

What It Helps Address

• 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 throttle response from degraded plug performance
• Ignition noise concerns in resistor-equipped systems

Installation Notes and Tips

• Verify thread diameter, reach, seat type, and heat range before installation.
• Confirm the engine calls for an 18 mm tapered-seat spark plug with a 0.9 pre-gap.
• Inspect ignition wires, distributor components, and coil condition when replacing plugs on older vehicles.
• Use the vehicle service specification for final gap verification if adjustment is required.
• Check application details carefully on Ford F-150, Ford F-250, Ford Bronco, Mercury Cougar, and Lincoln Continental models.

Quality Assurance

Denso manufactures this spark plug to defined dimensional and material specifications, including nickel electrode construction, copper core design, and a resistor element for ignition-system compatibility. The Denso 5008 is built for direct replacement use in listed applications and follows the brand’s conventional U-Groove product design.