Product Name: Automobile Engine Coolant Expansion Tank Storage Tank Radiator Expansion Tank Replacement Parts Accessories Material: Plastic. The tank features a strong, pressureresistant and frictionresistant design to maintain stability during use and reduce the risk of failure. Function: When the coolant pressure in the radiator exceeds the pressure cap setting value, the coolant passes through the pressure cap seal and flows into the radiator coolant overflow tank through the overflow pipe. Easy to install: Replacement coolant reservoir is reliable and can be easily replaced without modification or special tools. It is recommended to be installed by professionals to reduce problems during installation. Use scenarios: Replacement part during radiator service or coolant system maintenance on vehicles that use a plastic coolant expansion tank. Spare part for routine maintenance to ensure the overflow function operates correctly and to prevent coolant loss. Installed by professional technicians during engine cooling system repairs to restore proper overflow function and maintain system pressure.