Denso 3501 Spark Plug

Denso Iridium Long Life Spark Plug

The Denso 3501 is an Iridium Long Life spark plug built for OE-level performance, durability, and emissions control. It is a direct replacement choice for select Hyundai, Kia, and BMW applications, including Hyundai Accent, Sonata, Elantra, and Kia Optima, Sportage, and Sorento.

The Iridium Long Life line uses a patented iridium alloy center electrode with a platinum ground strap to support stable ignition performance over extended service intervals. Denso 3501 is engineered with a 0.8 mm pre-gap, 12.0 mm thread diameter, 26.50 mm reach, flat seat, 16.0 mm hex, 5000 ohm resistance, nickel ground electrode core, and copper center electrode core.

Key Features

• Iridium center electrode tip material for consistent spark delivery
• Platinum chip ground electrode tip design for long-life operation
• OE-style construction for factory-spec replacement service
• 5000 ohm resistor design to help control electrical noise
• 0.8 mm pre-gap for specified ignition performance
• Flat seat, 12.0 mm thread diameter, and 26.50 mm reach
• Compatible with select Hyundai Accent, Sonata, Elantra, Kia Optima, Sportage, Sorento, Rio, and BMW M2 applications

Product Details

Denso Iridium Long Life spark plugs are part of the brand’s OE-focused ignition lineup, built to meet strict performance, durability, and emissions standards. Part number 3501 cross-references DENSO Auto Parts ZXU22HCR8 for the same application. This spark plug is also listed with OEM interchange references for BMW and Hyundai applications, including Hyundai 18847-08220.

Use Denso 3501 when servicing ignition systems that require a long-life iridium plug with a platinum ground strap and factory-style dimensions. It is a direct service part for 2013-2016 Kia Optima, 2014-2015 Hyundai Sonata, 2014-2017 Hyundai Santa Fe Sport, 2014-2017 Kia Sportage, 2016-2017 Kia Sorento, 2016-2020 Hyundai Sonata, 2017-2020 Kia Optima, 2018 Kia Sorento, 2018-2019 Kia Sportage, 2019-2020 Hyundai Elantra, 2020 Kia Rio, 2021 Hyundai Accent, 2021 BMW M2, and 2022 Hyundai Accent.

What It Helps Address

• Hard starting caused by worn or fouled spark plugs
• Rough idle from inconsistent ignition output
• Misfire conditions related to plug wear or gap drift
• Reduced fuel economy from weak spark performance
• Emissions issues tied to degraded secondary ignition components

Installation Notes

Verify the specified thread diameter, reach, seat type, and pre-gap before installation. Inspect the ignition coil, boots, and plug wells for contamination or wear before fitting the new plug. Follow the vehicle service manual for torque and service procedures, and confirm application details against the exact engine code when servicing Hyundai Accent, Sonata, Elantra, Kia Optima, Sportage, Sorento, Rio, or BMW M2 models.

Quality Assurance

Denso manufactures this spark plug to OE performance, durability, and emissions standards. The Iridium Long Life design is intended for factory-style service replacement where consistent ignition quality and long service life are required.