Motorcraft SP546X Spark Plug – OEM Replacement for Ford Expedition, F-150, Super Duty, Navigator and Lincoln Mark LT

Overview

Motorcraft SP546X is a direct OEM replacement spark plug designed to deliver consistent ignition performance for a broad range of Ford and Lincoln vehicles. Built with a copper core, platinum electrode tip, and nickel ground electrode, this plug is engineered to withstand the heat and wear of gasoline engines while maintaining precise gaps and fitment you expect from Ford engineering standards.

Why choose Motorcraft SP546X

• Direct OEM replacement for engines that left the assembly line with the same components you install during service
• Copper core and platinum electrode tip with nickel ground electrode for reliable ignition and durable performance
• Meets the rigorous Ford Engineering standards and original equipment specifications

Durability and reliable combustion stand out in daily driving. The copper core assists with heat transfer, while the platinum tip and nickel ground electrode are selected for long life and stable operation under a variety of driving conditions. SP546X supersedes earlier variants to ensure compatibility with the engines of its era.

Compatibility and fitment

This spark plug is specified for a broad lineup, including Ford Expedition (2005-2008), F-150 (2004-2008), F-250/350/450 Super Duty (2005-2008/2005-2010), F-53 Motorhome Chassis (2006-2008), F-550 (2005-2010), and Lincoln models such as Mark LT (2006-2008) and Navigator (2005-2008). Each engine benefits from a matched plug that preserves original performance characteristics.

What to expect in daily driving

• Improved reliability and smoother starts under varied temperatures and loads
• Potential reduction in misfires, especially in older or higher-mileage engines
• Consistent fuel economy and reduced emissions within manufacturer specifications
• OEM-grade fit, ensuring proper reach, heat range, and gap for compatibility

Packaging and value

Packaging includes a single spark plug per box, aligning with standard OEM replacement practices. The compact dimensions (approximately 3.63 x 1 x 1 inches) make handling straightforward during maintenance and service intervals.