Bosch 6740 Spark Plug

Bosch OE Fine Wire Platinum Spark Plug 6740

Bosch OE Fine Wire Platinum spark plug 6740 is built for drivers who want OE-style ignition performance with a platinum center electrode and fine wire design. It delivers improved ignitability and fuel efficiency while meeting or exceeding original equipment specifications for platinum spark plugs.

Compatible with select Mitsubishi Eclipse, Galant, Lancer, and Outlander applications, this Bosch spark plug is a direct-fit secondary ignition service part for 2004-2012 model years covered by the fitment data.

Key Features

• Fine wire center electrode with platinum firing pin for consistent spark delivery
• Tapered ground electrode design for OE-style ignition performance
• Platinum center electrode tip material with nickel ground electrode tip material
• Resistor spark plug design with 6000 resistance
• Flat seat, 14 mm thread diameter, 26.5 reach, and 16 mm hex size
• Ceramic insulator with non-removable nut terminal
• Pre-gapped to .9 for OE-style service replacement

Product Details

Bosch OE Fine Wire Platinum 6740 is a 4-cycle spark plug engineered for secondary ignition systems that call for a platinum plug with OE-level specifications. The copper core center electrode supports stable conductivity, while the fine wire platinum tip helps promote reliable ignition under everyday driving conditions. This Bosch OE Fine Wire Platinum line focuses on practical replacement performance for vehicles that require a flat-seat, resistor-style spark plug.

This part cross-references Monroe Shocks & Struts (e.g., 172286, 182286) for the same application.

What It Helps Address

• Hard starting caused by worn or inefficient spark plugs
• Rough idle from inconsistent ignition output
• Reduced fuel economy linked to degraded spark performance
• Misfire symptoms related to worn plug electrodes
• Maintenance replacement for OE-style ignition service

Installation Notes

Verify the 14 mm thread diameter, 26.5 reach, flat seat, and 16 mm hex size before installation. Check the vehicle’s specified gap and compare it to the .9 pre-gap measurement before use. Confirm the correct application for Mitsubishi Eclipse, Mitsubishi Galant, Mitsubishi Lancer, or Mitsubishi Outlander model years listed in the fitment data.

• Fits 2006-2012 Mitsubishi Eclipse, N/A
• Fits 2004-2012 Mitsubishi Galant, N/A
• Fits 2004-2006 Mitsubishi Lancer, N/A
• Fits 2004-2006 Mitsubishi Outlander, N/A

Quality Assurance

Bosch designs this OE Fine Wire Platinum spark plug to meet or exceed original equipment specifications for platinum spark plugs. The part number is 6740.