What could cause an engine to run hot when a thermostat has been installed incorrectly?

When a thermostat is installed incorrectly and does not open, it prevents coolant from flowing through the engine's cooling system as needed. The thermostat acts as a gatekeeper for the coolant; when it remains closed, the engine cannot receive the necessary coolant to regulate its temperature. As the engine continues to run, the heat generated by the combustion process builds up without being dissipated, leading to overheating.

This scenario highlights the critical role of the thermostat in maintaining appropriate engine temperatures. If it fails to open due to incorrect installation, the engine can rapidly reach temperatures that could cause damage, leading to potential overheating issues.

Other potential scenarios, like a thermostat being stuck open or another aspect of the cooling system malfunctioning, would result in different behaviors of coolant flow. However, in this case, the incorrect installation directly affects the ability of the engine to cool down effectively.