Bosch 6739 Spark Plug

Bosch OE Fine Wire Platinum Spark Plug 6739

Bosch OE Fine Wire Platinum spark plug 6739 is built for drivers who want OE-style ignition performance with a platinum center electrode and fine wire design. It is engineered to improve ignitability and fuel efficiency while meeting or exceeding original equipment specifications for platinum spark plugs.

Compatible With Ford Escape, Lincoln Corsair, Ford Fusion, and other listed Ford, Lincoln, and Mercury applications, this Bosch spark plug is a direct-fit secondary ignition service part for a wide range of 4-cycle engines.

Key Features

• Fine wire center electrode with platinum firing pin for consistent spark delivery
• Tapered ground electrode design for OE-style combustion performance
• Resistor spark plug with 6000 resistance
• Copper core center electrode with platinum tip and nickel ground electrode materials
• 14 mm thread diameter, 25 mm reach, and 1.3 pre-gap size
• Non-projected ceramic insulator with tapered seat and J-gap ground configuration
• Bosch OE Fine Wire Platinum line is engineered as an economical upgrade from conventional copper core plugs

Product Details

Bosch 6739 is part of the OE Fine Wire Platinum product line, a Bosch spark plug family focused on OE-level fit and ignition consistency. The fine wire center electrode helps concentrate the spark, while the platinum tip supports stable performance over normal service intervals. This design is a practical choice for owners servicing Ford Escape, Lincoln Corsair, Ford Fusion, Ford Transit Connect, and related applications listed in the fitment data.

This part cross-references standard OE-style platinum spark plug applications for the same vehicle platforms.

What It Helps Address

• Hard starting caused by worn or inefficient spark plugs
• Rough idle from inconsistent ignition at the plug gap
• Reduced fuel economy related to weak spark delivery
• Misfire conditions tied to aged secondary ignition components
• Loss of throttle response from degraded plug performance

Installation Notes

Verify engine application, thread diameter, reach, seat type, and heat range before installation. Bosch 6739 uses a tapered seat, 14 mm thread, 25 mm reach, and a 1.3 pre-gap size, so matching the engine specification is important for proper sealing and combustion chamber fit. Inspect ignition coils and plug wires during service to avoid installing a new plug into a worn ignition system.

Fits 2009-2023 Ford Escape, N/A; Fits 2025-2026 Ford Escape, N/A; Fits 2021-2023 Lincoln Corsair, N/A; Fits 2025-2026 Lincoln Corsair, N/A; Fits 2006-2020 Ford Fusion, N/A; Fits 2011-2019 Lincoln MKZ, N/A; Fits 2013-2018 Ford C-Max, N/A; Fits 2009-2011 Mercury Mariner, N/A; Fits 2006-2011 Mercury Milan, N/A; Fits 2014-2022 Ford Transit Connect, N/A; Fits 2021 Ford Transit-150, N/A; Fits 2021 Ford Transit-250, N/A; Fits 2021 Ford Transit-350, N/A; Fits 2021 Ford Transit-350 HD, N/A; Fits 2022 Ford Explorer, N/A; Fits 2019-2020 Ford SSV Plug-In Hybrid, N/A.

Quality Assurance

Bosch engineers this spark plug to meet or exceed original equipment specifications for platinum spark plugs, supporting OE-style service quality for the listed Ford, Lincoln, and Mercury applications.