An illustrative example fuel cell cooler plate includes a first side configured to be received adjacent a fuel cell component and a second side facing opposite the first side. The first side defines a first surface area of the plate. An edge is transverse to the first side and the second side. The edge has a surface area that is less than the first surface area. A first coolant passage within the plate is closer to the second side than the first side. A second coolant passage is between the first side and the first coolant passage. The second coolant passage is in a heat exchange relationship with the first coolant passage.