NGK 5689 Spark Plug

NGK Iridium IX Spark Plug for OE-Style Ignition Performance

NGK Iridium IX Spark Plug 5689 is built for drivers who need precise ignition performance and stable operation in a wide range of import applications. This spark plug uses an iridium center electrode, a copper core, and a nickel ground electrode to support consistent spark delivery in demanding daily driving conditions.

Fits 1985-1994 Saab 900, N/A; Fits 1987-1990 Saab 9000, N/A; Fits 1987-1992 Toyota Supra, N/A; Fits 1990-1994 Aston Martin Virage, N/A. This part cross-references DENSO Auto Parts (e.g., 5302) for the same application.

Key Features

• NGK Iridium IX Spark Plug line for OE-style ignition service
• Part number 5689, also identified as BCPR6EIX
• Iridium center electrode tip for focused spark performance
• Copper core center electrode for heat transfer support
• Nickel ground electrode with standard configuration
• Pre-gapped at .032 inches
• 5,000 ohm resistance
• 14 mm thread diameter, .75 reach, flat seat, 5/8 hex

Product Details

NGK has long supplied original equipment spark plugs for domestic and import vehicles in North America, and this Iridium IX plug reflects that OE-focused engineering approach. The tapered-cut ground electrode tip and single-ground design support reliable ignition characteristics, while the iridium tip material helps maintain consistent spark quality under normal service conditions. Part number 5689 is a direct reference for BCPR6EIX applications, including Saab 900, Saab 9000, Toyota Supra, and Aston Martin Virage fitments listed below.

Common Issues This Spark Plug Can Address

• Rough idle caused by worn or inconsistent spark plugs
• Hard starting from degraded ignition performance
• Misfire conditions related to plug wear or incorrect gap
• Reduced throttle response from weak spark delivery
• Service replacement needs on high-mileage ignition systems

Installation Notes and Tips

Verify the engine application and match the listed fitment before installation. The pre-gap size is .032 inches, but several listed vehicles require a different gap setting in the notes, including 0.024, 0.028, or 0.032 inches depending on year and model. Use the manufacturer-specified gap for the exact application, and confirm the 14 mm thread diameter, .75 reach, flat seat, and 5/8 hex before installation. For Saab 900, Saab 9000, Toyota Supra, and Aston Martin Virage applications, follow the fitment notes shown for the correct gap specification.

Quality Assurance

NGK is a major OE spark plug supplier with more than 80 years of automotive manufacturing experience. The brand’s North American and global production and distribution network supports consistent product availability and OE-oriented quality standards for ignition service.