Systems and methods for diagnosing a thermostat

An apparatus, comprising:

• a controller comprising a memory coupled to a processor, the memory storing instructions that when executed by the processor cause operations comprising:
• receiving engine heat data indicative of a first amount of heat introduced into an engine;
• receiving heat loss data indicative of an amount of heat loss experienced by a coolant of the engine, wherein the heat loss data includes an ambient air temperature, and wherein the amount of heat loss is a predefined value based on the ambient air temperature;
• determining a temperature of the coolant based on the first amount of heat and the amount of heat loss;
• comparing the determined temperature of the coolant to a sensed temperature of the coolant;
• and
• determining a status of a thermostat responsive to the comparison.

A system, comprising:

• a liquid cooling system including a thermostat, the liquid cooling system structured to circulate a coolant;
• a controller coupled to the liquid cooling system, wherein the controller is structured to:
• receive engine heat data indicative of a first amount of heat introduced into an engine;
• receive heat loss data indicative of an amount of heat loss experienced by the coolant, wherein the heat loss data includes an ambient air temperature, and wherein the amount of heat loss is a predefined value based on the ambient air temperature;
• determine a temperature of the coolant based on the first amount of heat and the amount of heat loss;
• compare the determined temperature of the coolant to a sensed temperature of the coolant;
• and
• determine a status of the thermostat responsive to the comparison.