Denso 3523 Spark Plug

Iridium Long Life Spark Plug

Denso 3523 is an iridium long-life spark plug built to OE performance, durability, and emissions standards. It is a fitment-based replacement for select Lexus, Mazda, and Toyota applications, including Lexus LS500 and Mazda CX-5 models.

Key Features

• Iridium center electrode tip for stable ignition performance.
• Platinum needle ground electrode with needle-to-needle configuration.
• 5000 ohm resistor for controlled electrical noise suppression.
• Copper core center electrode and nickel ground electrode core for heat transfer and durability.
• Flat seat design with 0.7 mm pre-gap and 26.5 mm reach.

Detailed Description

This Denso spark plug, part number 3523, uses an iridium center electrode tip and a platinum needle ground tip to support consistent spark delivery under demanding operating conditions. The 14.3 mm hex, flat seat, and 26.5 mm reach make it a direct replacement style plug for confirmed applications across Lexus LS500, Lexus LX600, Mazda CX-30, Mazda CX-5, Mazda CX-9, Mazda 3, Mazda 6, Toyota Sequoia, and Toyota Tundra fitments. Denso 3523 is engineered for drivers replacing worn plugs in OE-spec ignition service intervals on modern gasoline engines.

The Spark Plug - Iridium Long Life (SIP) line focuses on long-service ignition components with fine-wire electrode construction and OE-level performance targets. For buyers searching for a Denso 3523 spark plug for Mazda CX-5 or a Denso 3523 spark plug for Toyota Tundra, this part matches the listed applications and specifications.

What It Is Used For

• Replacing worn spark plugs that cause rough idle.
• Restoring hard-start or extended-crank conditions.
• Addressing misfire codes related to ignition wear.
• Improving spark consistency when electrode wear has increased.
• Maintaining OE-spec ignition service on listed Lexus, Mazda, and Toyota models.

Installation Notes and Tips

Verify the listed fitment before installation, since application coverage varies by model year and engine package. Confirm the 0.7 mm pre-gap and seat type match the engine specification, and inspect coil boots and plug wells during service. Use the correct torque procedure for the cylinder head material and thread engagement.

Quality Assurance

Denso manufactures this plug to OE performance, durability, and emissions standards. Part number 3523 is supported by the brand's OE-focused ignition engineering and is cross-referenced to Monroe Shocks & Struts 172286 and 182286 for the same application.