A leak mitigation system for a cooling system may include an isolation valve, a controller, and a computer-readable medium. The isolation valve may selectively isolate an expansion tank from a closed loop containing a coolant circulated by a primary pump having a pump inlet. The expansion tank may maintain the coolant at a predetermined pressure at the pump inlet in the closed loop. The controller may communicate with the primary pump and the isolation valve. The computer-readable storage medium may include instructions executable by the controller to: in response to a detection of a leak of the coolant from the closed loop, shut down the primary pump; and close the isolation valve to isolate the expansion tank from the closed loop.