CSF Race-Spec Oil Cooler - BMW 135i/ M135i

N55-powered BMWs have become a favorite among track and performance drivers — but maintaining optimum oil temps is key to avoiding "cool down" laps and limp mode. Building on their proven BMW cooling expertise, CSF developed this upgraded oil cooler specifically for the N55 platform. Using AC Condenser Technology, this innovative dual-core in-series system adds 5 rows of super-high pressure multi-channel microtubes on the rear side of the cooler. Combined with a high-efficiency multi-louvered fin design, it delivers ~40% more heat rejection than the factory unit — keeping oil temps consistent and manageable even under extreme, extended driving conditions. It's a true drop-in fit, accepting all factory oil-line connections, mounting brackets, and shroud/ducting — no modifications required. Note: the added capacity increases total oil volume by 0.5 qt. (7.5 qts. vs. OEM's 7 qts.), so plan for the extra oil at install. Features Innovative 2-core in-series cooling system Front core with 14 rows, secondary backside cooler adds 5 more — ~40% increase in heat rejection Converted to single-pass design with high-pressure return line for optimal flow CSF AC Condenser Technology — 1-row, super-high pressure 26mm multi-channel microtube High-density, multi-louvered fin design for max surface area contact Drop-in fit, no modifications, accepts all OEM connections and hardware World's first true plug-and-play upgraded oil cooler for the N55 engine Track tested and proven by Hittman Racing's M235i endurance race car Requires 0.5 qt. additional oil at fill-up (7.5 qts. total) Fitment Year Range Make Chassis Model Engine 2012–2015 BMW F3X 335i Turbocharged 3.0L L6 2014–2016 BMW F3X 335i GT xDrive Turbocharged 3.0L L6 2012–2015 BMW F3X 335i xDrive Turbocharged 3.0L L6 2014–2016 BMW F3X 435i Turbocharged 3.0L L6 2015–2016 BMW F3X 435i Gran Coupe Turbocharged 3.0L L6 2014–2016 BMW F3X 435i xDrive Turbocharged 3.0L L6 2015–2016 BMW F3X 435i xDrive Gran Coupe Turbocharged 3.0L L6 2013–2015 BMW F3X ActiveHybrid 3 Turbocharged 3.0L L6 2014–2016 BMW F22/F23 M235i Turbocharged 3.0L L6 2015–2016 BMW F22/F23 M235i xDrive Turbocharged 3.0L L6