A coolant control system of a vehicle includes an adjusting module that: (i) receives an engine output coolant temperature measured at a coolant output of an internal combustion engine; (ii) adjusts the engine output coolant temperature based on a reference temperature to produce a first adjusted coolant temperature; (iii) receives an engine input coolant temperature measured at a coolant input of the internal combustion engine; and (iv) adjusts the engine input coolant temperature based on the reference temperature to produce a second adjusted coolant temperature. The coolant control system also includes a difference module that determines a difference between the first and second adjusted coolant temperatures. The coolant control system also includes a pump control module that controls a coolant output of a coolant pump based on the difference between the first and second adjusted coolant temperatures.