Bosch 8186 Spark Plug

Bosch OE Fine Wire Double Platinum Spark Plug

Bosch 8186 is an OE Fine Wire Double Platinum spark plug built for steady ignition performance and extended service life. It uses platinum on the center electrode and a platinum inlay on the ground electrode to help reduce gap erosion while maintaining OE-style specifications.

Compatible With select Audi and BMW applications, including Audi Q5, Audi S5, Audi A6, Audi A5 Quattro, and A4 Quattro, plus BMW 550i, 650i, X5, 750i, and 750Li applications. If you are replacing worn plugs on a 2006-2010 BMW X5 or a 2009-2012 Audi Q5, Bosch 8186 is built to match the required OE spark plug design.

• Fine wire center electrode for consistent spark delivery
• Double platinum design for improved wear resistance
• Resistor spark plug with 6000 ohm resistance
• 14 mm thread diameter, 19 mm reach, and flat seat
• Non-removable nut terminal with ceramic insulator
• J-gap ground configuration with standard tip design
• Heat range 7 for OE-style application matching

OE Fine Wire Double Platinum Design

The Bosch OE Fine Wire Double Platinum line focuses on original-equipment style construction for vehicles that require a durable platinum spark plug. Bosch 8186 uses a platinum firing pin on the center electrode and platinum at the ground electrode to help maintain the gap over time, supporting stable ignition performance in demanding daily driving conditions. This makes it a practical choice for drivers servicing Audi A6, Audi S5, BMW 550i, and similar applications where OE spark plug specifications matter.

Common Issues This Spark Plug Can Address

• Rough idle caused by worn spark plug electrodes
• Hard starting related to weak or inconsistent spark output
• Misfire symptoms from excessive gap wear
• Reduced ignition efficiency from aged factory plugs
• Service intervals that call for OE-style double platinum plugs

Installation Notes and Tips

Verify engine application by year, make, and model before installation. Bosch 8186 uses a 14 mm thread, 19 mm reach, flat seat, and non-removable nut terminal, so confirm the cylinder head specification matches these dimensions. Check the pre-gap size before installation and follow the vehicle manufacturer’s torque and service procedures. For best results, replace spark plugs on a cold engine and inspect ignition coils and boots during service.

Quality Assurance

Bosch builds this spark plug to meet Original Equipment specifications for double platinum applications. The platinum-on-platinum electrode design is used to improve durability and help maintain performance life in OE-required ignition systems.

Fitment

• Fits 2009-2012 Audi Q5, N/A
• Fits 2010-2012 Audi S5, N/A
• Fits 2009-2011 Audi A6, N/A
• Fits 2008-2010 Audi A5 Quattro, N/A
• Fits 2009 Audi A4 Quattro, N/A
• Fits 2006-2010 BMW 550i, N/A
• Fits 2006-2010 BMW 650i, N/A
• Fits 2006-2010 BMW X5, N/A
• Fits 2006-2008 BMW 750i, N/A
• Fits 2006-2008 BMW 750Li, N/A