A cooling system for use with a heat source is disclosed. The cooling system has an oil cooler, a fluid pump driving fluid through the cooling system, a first heat exchanger, and a first bypass line to direct fluid around the first heat exchanger. The cooling system also has a first electrically-controlled valve to selectively direct at least a portion of the fluid to at least one of the first heat exchanger and the first bypass line based on a fluid temperature. The cooling system further has a second heat exchanger, and a second bypass line to direct fluid around the second heat exchanger. The cooling system additionally has a second electrically-controlled valve located upstream of the oil cooler and configured to selectively direct at least a portion of the fluid to at least one of the second heat exchanger and the second bypass line based on an oil temperature.
 This invention was made with Government support under DOE Contract No. DE-FC26-04NT42189 awarded by the U.S. Department of Energy. Accordingly, the Government may have certain rights to this invention.