Radiator Coolant Overflow Tank Reservoir Toyota RAV4 Lexus NX200t NX300h (2006-2018) 2.0L 2.5LDirect Fit Radiator Coolant Overflow Tank Reservoir for 2006 2018 Toyota, Lexus Rav4, NX This coolant reservoir replaces compromised factory expansion tanks, ensuring proper fluid recovery and maintaining optimal system pressure. The Stock Rav4, NX Thermal Cycling Vulnerability Over thousands of miles, the factory OEM plastic coolant expansion tank on the XA30, XA40, and AZ10 chassis is subjected to severe thermal cycling. Operating in a high