Denso 5312 Spark Plug

Denso Iridium Power Spark Plug 5312

Denso Iridium Power spark plug 5312 is built for drivers who want precise ignition performance from a compact iridium design. It uses a 0.4 mm iridium center electrode, a 0.8 mm pre-gap, and a tapercut U-groove ground electrode layout to support consistent spark delivery in demanding engine conditions.

Key Features

• Iridium center electrode tip material for fine-wire ignition performance
• World’s smallest 0.4 mm iridium center electrode design, per manufacturer description
• Tapercut, U-groove ground electrode tip design
• 5000 ohm resistor for ignition noise suppression
• Copper core center electrode and nickel ground electrode core
• 14.00 mm thread diameter, 19.00 mm reach, and flat seat design
• 16.0 mm hex size for standard service-tool access
• Manufacturer heat range 27

Product Details

The Denso Iridium Power line focuses on fine-wire electrode geometry for efficient spark initiation and stable combustion. Part number 5312, also referenced as Denso IK27, is a spark plug designed around an iridium center electrode with a copper core for thermal control and a nickel ground electrode for durability. The tapercut and U-groove ground electrode profile helps concentrate the spark path, while the 0.8 mm pre-gap supports factory-style ignition setup. This spark plug is a direct-fit style service part for applications that call for these dimensions and heat range, including select Honda Civic and Toyota Corolla engine configurations where Denso 5312 is specified.

Common Symptoms It Can Address

• Rough idle caused by worn or fouled spark plugs
• Hard starting from weak ignition output
• Misfire codes related to degraded plug performance
• Reduced throttle response from inconsistent spark delivery
• Fuel economy loss tied to inefficient combustion

Installation Notes

Verify thread diameter, reach, seat type, heat range, and pre-gap before installation. Use the correct torque specification for the engine and inspect ignition coils, boots, and plug wires during service. For fitment-based searches, this part is commonly referenced for Denso 5312 spark plug replacement on select Honda Civic and Toyota Corolla applications where the IK27 cross-reference is specified.

Quality Assurance

Denso manufactures this Iridium Power spark plug to OE-style dimensional standards with an iridium fine-wire center electrode and resistor construction for stable ignition performance. Part number 5312 is cross-referenced as Denso Auto Parts IK27 for the same application.