CSF 2011+ BMW 1 Series M / 07-11 BMW 335i / 2009+ BMW Z4 sDrive30i/Z4 sDrive35i (A/T Only) Radiator - 7046

CSF has over 5 decades of experience manufacturing radiators. So when it comes to keeping your engine cool and your 1M/135i/335i/Z4 running at its best, a CSF High-Performance All-Aluminum Radiator is the obvious choice. Designed to perform on the street or at the track, a performance radiator is a must-have for both high horsepower builds as well as race vehicles which need added cooling performance in motorsports environments. This radiator features a 2-Row core with CSF's exclusive B-Tube Technology: Unlike a regular oval shape "O" type radiator tube, CSF uses a specially engineered tube in the shape of a "B". These "B-tubes" are carefully formed and then brazed over the seam to seal. CSF is able to use thinner and lighter aluminum material (with better cooling efficiency) because this design is actually stronger than normal "O" shape tubes that are welded. The design (inlet in the middle of the tube that is seam brazed) increases the heat transfer surface area of the tubes by approximately 15% over regular tubes - producing the efficiency of two smaller tubes vs. one large tube within the same space criteria. With "B-tubes" you are able to get "dual liquid laminar flow". CSF also uses ultra efficient multi louvered fins that are carefully and precisely aligned to maximize airflow through each radiator core. Fin specifications are carefully measured and calculated for each application, and tested for maximum heat rejection efficiency in our wind-tunnel lab.

The CSF 1M/135i/335i/Z4 radiator is a true "Drop-in fit" design requiring no modifications to install. OE style brackets are all CNC machined and welded for the best durability possible. Inlet/Outlet connections are designed to match the OE connections so you can reuse OEM hoses or aftermarket. Trust the cooling experts at CSF for the best performing, highest-quality, and most reliable radiators.

⚠ Fitment Notes

The CSF #7046 is only a replacement for the BMW 17117547059. BMW updated the part number for the radiator from 17117547059 (which the #7046 is based on) to the 17117788903 which does not have the extra port on the lower right-hand side.

CSF #7046 (BMW 17117547059)

BMW 17117788903

The update note from BMW states:

Acc. to NAEL EUY71B, this radiator (17117788903) should be installed instead of 17117547059 (in conjunction with blind socket 17122754235 to connect one of the now open coolant lines on the side of vehicle).

The fitment issue comes from this update. The independent circuit for the transmission cooler is removed with the 17117788903 radiator and the transmission cooler won't get proper coolant flow if you cap off the provision on the CSF #7046. If you have the BMW 17117788903 radiator already, you would need to convert back to the original setup with a hose running to the lower RH radiator port.

You should be able to add this connection back that was capped off by connecting hose 10 (BMW 17127548203 - diagram 1 below) to the CSF Radiator with Fitting 11 (BMW 17117548104 - diagram 2 below) and O-ring (BMW 17111711987).