A machine has a power source and a cooling system configured to circulate coolant between the power source and a heat exchanger. The cooling system has a first sensor configured to sense an ambient temperature and provide a first signal indicative of the ambient temperature and a second sensor configured to sense an actual temperature of the coolant and to provide a second signal indicative of the actual coolant temperature. The cooling system has a controller in communication with the first and second sensors to receive the first and second signals. The controller is configured to calculate, based on the ambient temperature and on a model for the heat exchanger, a predicted coolant temperature, and to compare the predicted coolant temperature to the actual coolant temperature. The controller is further configured to provide an alert based at least in part on the comparison.