Denso 3524 Spark Plug

Denso Iridium Long Life Spark Plug 3524

Denso 3524 is an Iridium Long Life (SIP) spark plug built for OE-level performance, durability, and emissions control. It uses an iridium center electrode, platinum needle ground tip, and a 0.8 mm pre-gap for consistent ignition in modern Toyota and Lexus engines.

Compatible With Toyota Camry, RAV4, Highlander, Sienna, Venza, Corolla, Prius, Prius Prime, Corolla Cross, Avalon, and Lexus ES250, ES300h, NX250, NX350h, NX450h+, RX350h, and UX250h applications where this OE-style plug is specified.

Key Features

• Iridium center electrode for stable spark performance
• Platinum needle ground electrode tip with needle-to-needle configuration
• 0.8 mm pre-gap for factory-style ignition setup
• 5000 ohm resistor for ignition noise suppression
• Copper core center electrode and nickel ground electrode core
• Flat seat design, 12.00 mm thread diameter, 26.50 mm reach
• Manufacturer heat range 16

Product Details

This Denso Iridium Long Life (SIP) spark plug is engineered to match strict OE performance, durability, and emissions standards. The iridium tip supports long service life, while the platinum needle ground design helps maintain consistent firing characteristics under everyday driving and high-efficiency hybrid operation. Part number 3524 cross-references Denso Auto Parts FC16HR-Q8 and Toyota 90919-01289 / 90919-A1001 for the same application.

Use Denso 3524 when servicing OE-specified ignition systems in late-model Toyota and Lexus vehicles, including 2020-2023 Toyota Camry, 2020-2023 Toyota RAV4, and 2019-2023 Lexus ES300h. It is also listed for 2023 Toyota Prius with a 0.032 gap note, along with other 2018-2023 Toyota and Lexus hybrid and gasoline applications shown in the fitment data.

What It Helps Address

• Hard starting caused by worn spark plug electrodes
• Rough idle from inconsistent ignition firing
• Misfire codes related to plug wear or gap drift
• Reduced fuel economy from degraded spark performance
• Emissions issues tied to weak combustion

Installation Notes

• Verify engine application and OE part number before installation.
• Confirm the specified gap for the vehicle; the listed pre-gap is 0.8 mm, and 2023 Toyota Prius fitment notes a 0.032 gap.
• Use the correct torque procedure for the aluminum cylinder head and flat-seat plug design.
• Inspect ignition coils and boots during service to avoid repeat misfire concerns.

Quality Assurance

Denso manufactures this spark plug to OE performance, durability, and emissions standards. The Iridium Long Life (SIP) product line is built for factory-style fitment and consistent ignition performance in the listed Toyota and Lexus applications.