CSF 97-02 Audi S4 (B5) Radiator

When you're working on your 2000-2002 Audi S4, especially if it's a high-horsepower build or sees track time, keeping that engine cool is critical. This all-aluminum radiator from CSF is built to handle the extra heat. CSF has been making radiators for over 50 years, so they know what it takes to keep engines running at their best.

What makes this radiator stand out is its B-tube technology. Instead of a standard oval tube, CSF uses a specially shaped tube that's seam-brazed for strength. This design increases the heat transfer surface area by about 15% compared to regular tubes, giving you the cooling efficiency of two smaller tubes in the same space. It also uses multi-louvered fins that are precisely aligned to maximize airflow and heat rejection, all tested in their wind tunnel lab. The core is a 2-row, 42mm design, offering substantial cooling capacity.

You get a true drop-in fit with this radiator, meaning no modifications are needed for installation. It's designed to accept all your original equipment components, including the AC condenser, mounting brackets, and fan shroud. The inlet and outlet connections are made to match the factory specs, so you can reuse your original hoses. It also includes CNC machined brackets and fittings for a solid, durable connection, and a smooth satin finish with an all-aluminum race-style drain plug.