Which issue is likely to arise from a thermostat stuck open?

When a thermostat is stuck open, it allows coolant to flow continuously through the engine, which prevents the engine from reaching its optimal operating temperature. This can lead to inefficient fuel combustion and performance issues, as the engine may run too cool. Cooler engine temperatures can prevent the oil from reaching its ideal viscosity and can lead to incomplete combustion, which in turn increases emissions.

Engine overheating is associated with thermostats that are stuck closed, as they block the flow of coolant. Therefore, a thermostat that remains open leads to a consistent flow of coolant, which may appear contrary to causing overheating directly. However, the malfunction can still cause a chain reaction that affects overall engine performance and could eventually result in overheating due to other systemic failures, like insufficient oil temperature.

Maintaining the proper functioning of the thermostat is crucial for balancing engine temperature, ensuring heat is properly dissipated, and allowing for efficient engine operation. Hence, while the scenario describes a thermostat stuck open, it can contribute to a systemic issue that might eventually lead to overheating under specific conditions.