The heat exchanger of the present invention has a charge air cooler stacked upstream of a jacket water cooler. The charge air cooler is split into two sections. Each section has a vertical tank and header on the outside of the charge air cooler. Charge air enters the respective tanks and then horizontally flows to a vertical center tank, where it flows vertically to the outlet, and is routed to the engine. Maximum entering temperature differentials in the charge air cooler occurs at the sides of the cooler, as does maximum heat energy transfer. The air passing through the middle of the charge air cooler (adjacent the vertical center tank) gains the least amount of heat energy. The jacket water cooler can be a vertical flow cooler. A significant portion of the jacket water cooler at the middle of the jacket water cooler operates at increased entering temperature differential.