What is the main benefit of a clear polycarbonate expansion tank?

A clear polycarbonate tank allows you to easily see the coolant level without having to remove the cap. This makes it simple to monitor your engine's cooling system health and identify potential leaks or low coolant situations quickly.

Is this expansion tank difficult to install on my Miata?

No, this Moroso expansion tank is designed as a direct bolt-in replacement. This means it should install using the factory mounting points and connections, typically requiring only basic hand tools and no modifications.

What does the Prop 65 warning mean for this product?

The Prop 65 warning indicates that the product contains chemicals known to the State of California to cause cancer or reproductive harm. This is a regulatory requirement and does not necessarily mean the product is unsafe when used as intended.

Moroso 06-15 Mazda Miata Coolant Expansion Tank - Direct Bolt-In Replacement

Specifications

Brand: Moroso
Part #: 63779
UPC: 84663637797

Moroso 06-15 Mazda Miata Coolant Expansion Tank - Direct Bolt-In Replacement

Name: Moroso 06-15 Mazda Miata Coolant Expansion Tank - Direct Bolt-In Replacement
Brand: Moroso
Price: 355.99 USD
Availability: InStock

$355.99

On Backorder — Expected to ship by Apr 3, 2026

Order now to reserve yours — we'll ship as soon as stock arrives. Full refund if we're unable to fulfill.

Key Features

Fits 2006-2015 Mazda Miata.
Constructed from clear polycarbonate for easy coolant level monitoring.
Designed as a direct bolt-in replacement for the factory tank.
Helps maintain proper engine cooling system function.
Features a Prop 65 warning as specified by the manufacturer.

This expansion tank is designed to fit 2006-2015 Mazda Miata models. Please verify fitment for your specific vehicle.

⚠️ CA WARNING: This product can expose you to chemicals known to the State of California to cause cancer and/or birth defects or other reproductive harm. Learn more

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Product Details

This Moroso coolant expansion tank is made from a durable, clear polycarbonate, allowing you to easily monitor your coolant level at a glance. It's designed as a direct bolt-in replacement for the factory plastic tank on your 2006-2015 Mazda Miata, meaning you won't need to modify anything to get it installed. The clear material helps you keep an eye on your engine's cooling system health, ensuring you can catch any potential issues before they become serious problems.

Moroso is known for well-built performance parts, and this expansion tank is no exception. The polycarbonate construction offers good resistance to heat and chemicals found in a cooling system. Because it's a direct replacement, installation is straightforward, often just requiring you to transfer a few hoses and mounting hardware from your old tank. This makes it a practical upgrade for any Miata owner looking to maintain or improve their cooling system's reliability.

Please be aware that this product is subject to California Proposition 65 warnings, as indicated by the manufacturer.