Cobb Subaru 15-21 WRX/STI Coolant Overflow Tank

The COBB Subaru 15-21 WRX/STI Coolant Overflow Tank does not have enough exact application evidence to assign safe vehicle YMM. Match manufacturer part number 800660, complete vehicle, engine and transmission configuration, factory equipment, required calibration, emissions eligibility, interfaces, and every product note before ordering.

Key Features

• Billet Aluminum Build: Resists cracking and corrosion far better than OEM plastic, ensuring long-term reliability in high-heat conditions.
• 50% Increased Capacity: Provides extra coolant volume (1.5L vs. OEM ~1L) to prevent overflow and maintain system pressure.
• Complete Kit: Includes aluminum cap, stainless steel hardware, and O-ring seals for plug-and-play installation.
• Internal Baffling: Reduces fluid movement and air pockets, promoting stable temperatures under boost.
• Bolt-on fit requires basic hand tools 30-45 minutes for experienced installers.
• Precision CNC-machined parts tested in real-world high-performance applications.

Fitment

Specifications

What’s Included

One new COBB product in the exact configuration and quantity identified by manufacturer part number 800660. Calibrations, hardware, hoses, clamps, gaskets, adapters, wiring, fluids, tools, and companion components are included only when expressly stated for this exact part number.

About COBB

COBB develops engine-management, intake, cooling, exhaust, drivetrain, suspension, and vehicle-accessory products for supported performance platforms. Correct selection remains exact-vehicle, exact-configuration, exact-interface, and exact-part-number specific.

Related COBB Products

• Cobb 04-07 Subaru WRX / STI Coolant Overflow Tank w/ Washer Fluid Relocation Kit
• Cobb 08-14 Subaru WRX/STI Coolant Overflow Tank
• Cobb 22-23 Subaru WRX Coolant Overflow Tank

Browse the COBB collection for related tuning, intake, cooling, exhaust, drivetrain, and chassis products.

Frequently Asked Questions

Why is fitment verification required for this COBB product?
Exact vehicle application evidence is not complete enough for safe YMM. Confirm the vehicle, drivetrain, factory equipment, calibration, emissions eligibility, interfaces, and exact part number before ordering.

Are all supporting parts included?
Only components expressly listed for the exact manufacturer part number are included. Tuning, hardware, hoses, clamps, gaskets, adapters, wiring, fluids, and companion components may be separate.

Is tuning or calibration required after installation?
Requirements depend on the exact product and vehicle. Intake, fuel, boost, turbo, and engine-management changes may require a compatible calibration before operation.

Installation Instructions

Follow the current COBB and factory service instructions for this exact part number. Verify fitment, factory equipment, emissions eligibility, required calibration, software and firmware, interfaces, hardware, fluid or electrical connections, and clearances before installation. Inspect the completed work and confirm safe operation before full-load use.