Denso 5359 Spark Plug

Denso Iridium Power Spark Plug 5359

Denso Iridium Power spark plug 5359 is built for drivers restoring or maintaining older Volkswagen Beetle, Buick LeSabre, Buick Skylark, and Oldsmobile Cutlass applications. It uses a fine 0.4 mm iridium center electrode to support stronger ignition performance and precise spark delivery in compatible secondary ignition systems.

Key Features

• Iridium center electrode tip material for focused spark performance
• World’s smallest 0.4 mm iridium center electrode design, per manufacturer description
• Tapercut and U-groove ground electrode tip design
• 5000 ohm resistance for ignition system compatibility
• 0.8 pre-gap size for direct-fit service on listed applications
• Copper center electrode core with nickel ground electrode core material
• Flat seat, 14.00 mm thread diameter, 12.70 mm reach, and 20.6 mm hex size

Product Details

This Denso Iridium Power line spark plug is engineered around a fine-wire iridium center electrode to improve ignition efficiency and maintain consistent spark characteristics. The 5359 part number is listed for a range of classic applications, including Fits 1954-1979 Volkswagen Beetle, N/A, Fits 1967 Buick LeSabre, N/A, Fits 1966-1967 Buick Skylark, N/A, Fits 1962-1964 Buick Skylark, N/A, and Fits 1962 Oldsmobile Cutlass, N/A. This part cross-references DENSO Auto Parts (e.g., IWF16) for the same application.

What It Helps Address

• Hard starting caused by worn or inconsistent spark plugs
• Misfire concerns related to degraded ignition performance
• Rough idle from weak spark delivery
• Reduced throttle response in aging ignition systems
• Service replacement needs for listed Volkswagen Beetle, Buick Skylark, Buick LeSabre, and Oldsmobile Cutlass applications

Installation Notes

Verify thread diameter, reach, seat type, and hex size before installation. The pre-gap size is listed at 0.8, but final gap should always be checked against the vehicle service specification. Confirm the ignition system is in good condition and inspect plug wires, cap, and coil during service on classic Volkswagen Beetle, Buick Skylark, Buick LeSabre, and Oldsmobile Cutlass models.

Quality Assurance

Denso’s Iridium Power line focuses on fine-wire iridium electrode construction and application-specific fitment. Part number 5359 is built to the listed dimensional and electrical specifications for the confirmed vehicle applications.