An electric motor which has a separate end cap heat exchanger, through which a liquid coolant is passed, is disclosed. In one example embodiment, the electric motor is a traction motor or motor-generator in a hybrid electric vehicle having an internal combustion engine. Additionally, in one embodiment, the heat exchanger has a low-temperature coolant loop configured to extract energy from the motor coolant. The electric motor may be installed in a variety of vehicles or other applications having greatly differing cooling requirements. By placing the heat exchanger and control componentry in the end cap, the cooling capability of the electric motor can be changed by selecting an end cap with the appropriate heat transfer characteristics and control componentry to provide the desired cooling. Consequently, a single electric motor, with a variety of end cap choices, can be used in a variety of applications.