1.When Should I Replace My Coolant Reservoir Tank? A coolant reservoir is part of the engine cooling system and is a small plastic container attached to the radiator or engine block. Its main function is to collect and store excess coolant that expands when heated, and it plays a very important role in the cooling system. If your car is experiencing problems such as engine overheating, low coolant levels, leaks, and coolant odor, you may need to replace your coolant reservoir. 2.Replacement Part Numbers 603278, 603278, CV6Z8A080C, CV6Z8A080B. Please check the detailed description or enter Year/Make/Model to check your compatibility before purchasing this radiator overflow tank. 3.Compatible with Select Ford Models 2013 2016 Ford Escape L4 2.0L, 2013 2016 Ford Escape L4 2.5L, 2013 2018 Ford Focus L4 2.0L, 2017 2018 Ford Focus L4 2.3L, 2014 2022 Ford Transit Connect L4 2.5L. 4.Direct Replacement Perfect match, direct replacement. When replacing the coolant overflow tank, please turn off the car and wait for the tank to cool down before proceeding. This coolant reservoir replacement is made from premium materials to ensure superior quality and longlasting performance. This is not a genuine part, but an aftermarket replacement.