CSF's high-performance all-aluminum radiator is a direct drop-in upgrade for automatic-transmission BMW 135i, 335i, X1, and Z4 models, built for street and track use on higher-horsepower and race builds. It runs a 2-row 42mm dual core using CSF's B-Tube technology, which raises heat-transfer surface area by roughly 15% over conventional round tubes, with 6.5mm multi-louvered fins for maximum airflow. The radiator accepts all OEM components including the quick-connect hoses, AC condenser, mounting brackets, and fan shroud with no modifications.
| Type | High-performance all-aluminum radiator (CSF B-Tube) |
| Core | 2-row 42mm dual core |
| Fins | 6.5mm multi-louvered |
| Included | CNC-machined quick-connect inlet/outlet, all-aluminum race-style drain plug |
| Finish | Smooth satin |
| Fit | Automatic transmission; drop-in, accepts OEM hoses, AC condenser, brackets and fan shroud |
This part fits:
| Year | Make | Model | Submodel |
|---|---|---|---|
| 2008-2013 | BMW | 135i | Base |
| 2013 | BMW | 135is | Base |
| 2007-2013 | BMW | 335i | Base |
| 2013-2015 | BMW | X1 | sDrive28i |
| 2013-2015 | BMW | X1 | xDrive28i |
| 2012-2016 | BMW | Z4 | sDrive28i |
| 2009-2016 | BMW | Z4 | sDrive35i |
