CSF 99-06 BMW 323i / 99-05 BMW 325i / 99-06 BMW 328i / 99-05 BMW 330i / 03-05 BMW Z4 Radiator

CSF has been making radiators for over 50 years, so they know a thing or two about keeping engines cool. If you're working on a BMW 3 Series from 1999 to 2006, or a Z4 from 2003 to 2005, this all-aluminum radiator is a solid choice to ensure your engine stays at the right temperature, whether you're on the street or the track.

This radiator uses CSF's unique B-Tube technology. Instead of a standard oval tube, these B-tubes are shaped and brazed for a stronger, lighter design that actually improves heat transfer by about 15% compared to regular tubes. It's like having two smaller tubes working together in the space of one large one, allowing for better airflow and more efficient cooling. CSF also uses precisely aligned, multi-louvered fins that are tested in a wind tunnel to maximize heat rejection. The brackets and connections are CNC machined for a precise fit, and it's designed as a direct replacement, meaning it fits right in without needing any modifications, and you can reuse your original hoses and mounting hardware.