CSF BMW E9X M3 Triple Pass RadiatorProduct Information High performance dual core, triple pass radiator which offers higher system capacity and a 20% increase in cooling system efficiency. 100% aluminum construction. The radiator core features an ultra efficient fin with 6. 5mm fin height and multi louvered design for maximum surface area contact. The triple pass flow structure allows the coolant to flow across the core of the radiator 3 times before exiting the radiator for lowest