Denso 5013 Spark Plug

Denso 5013 U-Groove Spark Plug Overview

Denso 5013 is a conventional spark plug built for older Ford and Mercury applications that call for a tapered-seat, 18 mm plug with a 0.9 pre-gap. Its U-Groove ground electrode design is engineered to improve ignitability, helping support more consistent combustion and engine efficiency in the right application.

For drivers servicing classic Ford Mustang, Thunderbird, Bronco, and Mercury Cougar or Marquis models, this Denso U-Groove Conventional spark plug offers the core dimensions and electrode construction needed for direct replacement service.

Key Features

• U-Groove ground electrode tip design for improved spark exposure
• Nickel ground electrode tip and nickel center electrode tip materials
• Copper center electrode core for stable heat transfer
• 5000 ohm resistor design for ignition system noise control
• Standard ground configuration with a single ground electrode
• Tapered seat, 18.00 mm thread diameter, and 11.60 mm reach
• Manufacturer heat range 20 with a 0.9 pre-gap size

Product Details

This Denso U-Groove Conventional spark plug, part number 5013, is part of Denso’s U-Groove line, a conventional spark plug family focused on reliable ignition performance in older engine platforms. The U-shaped ground electrode helps expose the spark kernel more effectively than a standard flat design, while the copper core and nickel electrode materials support dependable operation in the specified heat range. This part cross-references Denso Auto Parts MA20PR-U for the same application.

Compatible With select Ford and Mercury vehicles including 1957-1959 Ford F-100, 1964-1968 Ford Mustang, 1966-1971 Ford Bronco, 1966-1968 Ford Thunderbird, 1967-1971 Mercury Cougar, and 1967-1971 Mercury Marquis. The Denso 5013 is also listed for later Ford E-Series vans and trucks in the 1989-1996 model years.

Common Issues This Spark Plug Can Address

• Hard starting caused by worn or inefficient spark plugs
• Rough idle from inconsistent ignition at the plug gap
• Misfire symptoms related to aged secondary ignition components
• Reduced combustion efficiency in older Ford and Mercury engines
• Ignition noise concerns in resistor-equipped systems

Installation Notes and Tips

• Verify thread diameter, reach, seat type, and heat range before installation.
• Check the gap against the engine specification before use; the listed pre-gap is 0.9.
• Inspect plug wires, distributor components, and coil condition during service.
• Use proper torque for tapered-seat spark plugs to avoid sealing issues.
• Confirm vehicle-specific fitment for your Ford Mustang, Bronco, Thunderbird, or Mercury application.

Quality Assurance

Denso manufactures this spark plug as part of its conventional U-Groove ignition line, using specified electrode materials and dimensions for the listed applications. Part number 5013 is built to the published OE-style fitment and construction details shown above.