KOYO Aluminum Radiator Filler Neck

2017–2020 Toyota 86 / 2013–2020 Subaru BRZ / 2013–2016 Scion FR-S

FN2320

Overview:

The KOYO Aluminum Radiator Filler Neck is a premium upgrade designed specifically for the Toyota 86 (2017–2020), Subaru BRZ (2013–2020), and Scion FR-S (2013–2016). This component replaces the factory plastic filler neck with a durable, all-aluminum alternative that enhances both reliability and engine bay aesthetics. Ideal for enthusiasts seeking a robust and stylish cooling system upgrade, this filler neck withstands higher temperatures and resists cracking or warping common with plastic parts.

Whether you drive your vehicle daily or push it on spirited drives and track days, the KOYO Aluminum Radiator Filler Neck offers a dependable solution that improves longevity and adds a polished look under the hood.

Key Features:

Engineered for quality and performance, this filler neck includes the following features:

• Constructed from high-grade aluminum for superior strength and heat resistance compared to factory plastic.
• 100% TIG-welded construction ensures a precise, leak-free seal and long-lasting durability.
• Finished with a mirror polish that enhances engine bay appearance and resists corrosion.
• True drop-in replacement requiring no modifications, preserving factory fitment and function.
• Compatible with Koyorad SK-C13 type pressure caps or equivalent deep plunger caps for proper sealing and pressure management.
• Designed to withstand the demanding conditions of performance driving and daily use.

Construction & Design:

The filler neck is expertly crafted from lightweight aluminum, chosen for its excellent thermal conductivity and resistance to heat-related degradation. The 100% TIG welding process creates strong, clean joints that prevent leaks and maintain structural integrity over time. The mirror-polished finish not only adds a sleek, professional look but also provides a protective layer against oxidation and corrosion, ensuring the part maintains its appearance and performance for years.

Its design mirrors the factory part’s dimensions and mounting points, making installation straightforward and preserving the original cooling system layout without compromise.

Installation & Fitment:

This KOYO Aluminum Radiator Filler Neck is a direct bolt-on replacement for the specified Toyota 86, Subaru BRZ, and Scion FR-S model years. Installation is quick and simple, typically taking less than five minutes with basic hand tools. No cutting, drilling, or special tuning is required, making it an accessible upgrade for enthusiasts and mechanics alike.

• Fits 2017–2020 Toyota 86
• Fits 2013–2020 Subaru BRZ
• Fits 2013–2016 Scion FR-S
• Requires use of Koyorad SK-C13 or equivalent deep plunger pressure cap (OEM pressure caps are not compatible)

What’s Included

• One aluminum radiator filler neck with TIG-welded construction and mirror polish finish
• Installation instructions

Ideal For:

This filler neck is perfect for owners of the Toyota 86, Subaru BRZ, and Scion FR-S who want to replace the factory plastic filler neck with a more durable and visually appealing component. It suits daily drivers, weekend enthusiasts, and track day participants who demand reliability and style from their cooling system components.

Koyorad (Koyo) builds cooling system upgrades, including application-specific aluminum performance radiators designed to improve heat rejection for hard-driven street and track vehicles. It’s a trusted choice for boosted and high-revving builds where controlling coolant temps is critical to consistent power and reliability.