Saturn Ion engine runs warm at idle but cool when moving on Saturn Ion

Some Saturn Ion owners report experiencing engine overheating at idle while the temperature remains cool during movement. This issue may be attributed to a faulty thermostat, which can cause the temperature gauge to rise at idle, indicating a need for replacement. Additionally, a malfunctioning water pump may hinder coolant circulation, particularly at low RPMs, leading to inefficient cooling. Problems within the cooling system, including low coolant levels or other component failures, can exacerbate overheating at idle. Some owners also note that issues with the AC system, such as warm air from the vents, may contribute to the engine running hot when stationary. Furthermore, a sticking idle air control valve might cause the engine to idle at higher RPMs, resulting in overheating. It is advisable for owners experiencing these symptoms to check the thermostat, inspect the water pump, and evaluate the cooling system, AC system, and idle air control valve to prevent further overheating issues.