Replace an ageing or cracked coolant overflow bottle with Mazda’s own Revision C reservoir, supplied with its matching OEM cap. Restores factory-correct overflow containment across every RX8 from 2003 to 2012.
$250
The Mazda RX8 radiator sub tank Revision C is Mazda’s own evolved coolant overflow reservoir. It is supplied complete with its matching OEM cap and fits every SE3P built from 2003 to 2012.
Repeated heat cycles cause the original plastic bottle to cloud, distort or develop hairline cracks. This compromises both visible coolant-level checks and secure overflow containment. This genuine coolant expansion tank is the replacement Mazda engineered and validated for the Renesis platform, not a third-party interpretation.
For RX8 enthusiasts refreshing the cooling circuit, the overflow reservoir is one piece of a larger picture. A new-condition tank restores clarity to coolant-level checks at every cold start. The official Mazda Australia website carries further genuine-parts information for RX8 owners.
It also gives you confidence that the overflow side of the system is sealed correctly, removing one ageing variable from an already heat-intensive engine bay.
To complete a full cooling-system refresh alongside this genuine Mazda RX8 radiator sub tank, the GENUINE MAZDA OEM Radiator Hose Replacement Set renews every hose between radiator and engine in one go, keeping all joints in known condition. For Series 1 owners, the BEATRUSH Engine Cooling Under Panel Tray improves airflow management through the engine bay and works well with a freshened cooling circuit. For Series 2, the AUTOEXE x KOYORAD High-Capacity 48mm Aluminium Radiator is the logical next step when you want to lift the entire system’s heat-rejection capacity.
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Related RX8 Upgrades
The Mazda RX8 radiator sub tank Revision C fits every SE3P model from 2003 to 2012, covering both Series 1 and Series 2 without any modification or adaptation required.
The reservoir comes supplied with its matching OEM cap, so both components can be renewed together. You won't be left running a fresh tank alongside a worn cap of unknown condition.
Revision C reflects Mazda's own engineering and validation history for this part. It is an evolved version of the original reservoir, addressing the known ageing and cracking issues at the source rather than being a third-party interpretation of the original design.
This reservoir cross-references to Mazda part number N3H115350M. Owners verifying fitment or sourcing records can use that reference to confirm this is the correct factory replacement.
Repeated heat cycles cause the original plastic bottle to cloud, distort, or develop hairline cracks over time. These issues compromise both accurate coolant-level checks at a cold start and secure overflow containment, making the tank worth inspecting on any higher-mileage RX8.
As Mazda's own validated replacement for the Renesis platform, this tank is engineered to the same specification as the original. Genuine parts also carry the assurance of factory-correct fit and materials, which matters when the component's job is to contain coolant safely across a heat-intensive engine bay.
For a thorough cooling-system refresh, renewing the radiator hoses alongside the sub tank keeps every joint and vessel in known condition. Series 1 owners can also look at the Beatrush Engine Cooling Under Panel Tray for improved airflow management, while Series 2 owners may consider the AUTOEXE x KOYORAD 48mm aluminium radiator if lifting overall heat-rejection capacity is the goal.
