Wikipedia
Coolpower
A coolpower setup in a truck engine uses an aftercooler on the cylinder head and a tip turbine fan to draw heat away from the cylinder head and ram air over the aftercooler. Large Mack trucks from the 1970s such as the Mack R-600 used coolpower systems. Some coolpower systems used vertical bar shutters that could be opened and shut in front of the radiator to maintain proper operating temperature.
The Mack Cruise Liner model built in 1984, a 6X4 Primemover, used a coolpower engine.