CSF 3954 Radiator

CSF 3954 Radiator for Lexus RX and Toyota Sienna

The CSF 3954 radiator is an OE-style replacement built with an aluminum core and plastic tanks for direct-fit cooling performance. It is engineered for the 2021-2025 Toyota Sienna and 2023-2025 Lexus RX350, RX350h, RX450h+, and RX500h, with an upgraded heavy-duty core that is 11% thicker than the OEM 27mm design.

Key Features

• Part number 3954 radiator for select Lexus and Toyota applications
• Cross flow design with a single-row aluminum core
• Plastic tank and aluminum core construction
• Core thickness: 1 3/16 in.
• Core dimensions: 21 in. wide x 27 9/16 in. long
• Inlet: 1 1/2 in. left; outlet: 1 1/2 in. right
• Upgraded heavy-duty core, 30mm vs. OEM 27mm
• CSF radiators are engineered and wind tunnel tested for cooling validation

Detailed Description

CSF part number 3954 is a direct replacement radiator designed for modern Toyota and Lexus cooling systems. It uses an OE-style plastic tank and aluminum core layout, with a thicker heavy-duty core to improve cooling capacity over the factory 27mm unit. This radiator is listed for 2021-2025 Toyota Sienna and 2023-2025 Lexus RX350, RX350h, RX450h+, and RX500h, making it a fitment-focused choice for owners searching for a Lexus RX radiator or Toyota Sienna radiator replacement.

CSF manufactures radiators to high-performance standards and validates cooling performance through laboratory wind tunnel testing. The brand also supplies a wide range of radiator models across many vehicle platforms, which supports consistent application coverage and OE-style fitment. This part cross-references Toyota/Lexus OE numbers such as 16400-25200 and 16400-F0110 for the same application.

Common Problems This Radiator Can Address

• Cracked or leaking radiator tanks
• Restricted coolant flow from an aging core
• Overheating caused by reduced heat rejection
• Cooling system wear on high-mileage vehicles
• Replacement needs after collision or corrosion damage

Installation Notes and Tips

Verify radiator dimensions, inlet and outlet orientation, and vehicle application before installation. This radiator uses a cross flow layout with left-side inlet and right-side outlet connections. The radiator cap is not supplied, and no oil cooler is included. For best results, inspect hoses, clamps, and coolant condition during replacement on the Toyota Sienna or Lexus RX platform.

Quality Assurance

CSF radiators are manufactured in ISO/TSO-certified facilities and are engineered to meet high-performance cooling standards. The design is validated through laboratory testing to confirm cooling performance for the listed applications.