One Stop Solutions 2557 Radiator

Radiator for Audi A4, S4, and RS4

One Stop Solutions 2557 is a crossflow radiator built for select Audi applications with OE-style form and function. It uses premium-grade aluminum construction with plastic tanks, a single-row core, and 1 1/4-inch inlet and outlet diameters to support proper coolant flow and factory-style fitment.

Fits 2004-2009 Audi S4, N/A; Fits 2003-2008 Audi A4, N/A, wo/EOC; Fits 2007-2008 Audi RS4, N/A; Fits 2003-2005 Audi A4 Quattro, N/A, wo/EOC; Fits 2002 Audi A4, N/A; Fits 2002 Audi A4 Quattro, N/A.

• Core height: 24 13/16 in.
• Core width: 16 1/16 in.
• Core thickness: 1 in.
• Crossflow design with one-row core
• Plastic tank construction with PA core material
• Inlet and outlet header lengths: 16 11/16 in.
• Inlet and outlet header widths: 1 13/16 in.
• Inlet diameter: 1 1/4 in.; outlet diameter: 1 1/4 in.
• No engine oil cooler, transmission oil cooler, or cap included

OE-Style Cooling Performance

This radiator is engineered to match original equipment dimensions and function for Audi A4, Audi A4 Quattro, Audi S4, and Audi RS4 applications. The design uses cadmium-plated tubes to help resist premature failure, a die-cut gasket to support leak resistance, and factory-spec component fitment for a direct replacement on vehicles listed for part number 2557.

This part cross-references Spectra Premium CU2557 and APDI 8012556 for the same application.

Common Problems This Radiator Addresses

• Coolant leaks from a worn or damaged radiator core or tank
• Overheating caused by restricted coolant flow or reduced heat transfer
• Cracked or aging plastic end tanks on higher-mileage vehicles
• Poor fitment after a previous replacement radiator installation
• Cooling system performance loss on Audi A4, S4, and RS4 models

Installation Notes and Fitment Tips

Confirm vehicle configuration before installation, especially for 2003-2008 Audi A4 and 2003-2005 Audi A4 Quattro models listed without EOC. Verify inlet and outlet sizes, header dimensions, and crossflow layout against the original radiator before removal. Part number 2557 is built for drop-in style replacement, but cooling system inspection should include hoses, clamps, and coolant condition during service.

Quality Assurance

OSC radiators are individually pressure tested during production, with testing performed before cooler installation, after core assembly, and again on the completed unit. The design also incorporates engineering updates aimed at improving durability and service life in higher-mileage vehicles.