The Expansion Tank (OEM Number 164700T040) for the Toyota Corolla 2014–2015 (Petrol Unleaded) is a vital OEM component of the vehicle’s cooling system, designed to manage coolant expansion and maintain stable pressure during engine operation. Constructed from durable, heat-resistant plastic, it features a translucent body for easy visual monitoring of coolant levels and a pressure-rated cap (typically 1.0–1.2 bar) to ensure system integrity. With a capacity of approximately 1–1.5 liters, it stores excess coolant as the engine heats up, preventing overflow and pressure surges, then returns coolant to the system as temperatures drop. Integrated with OEM-specific mounting brackets and hose connections, it minimizes air pockets, reduces coolant evaporation, and safeguards critical components like the radiator, water pump, and engine block. Its corrosion-resistant design ensures longevity and reliable performance in daily driving and varying climates. Compatible exclusively with 2014–2015 Corolla petrol models, this tank preserves cooling efficiency and prevents overheating.