Temperature gauge climbs when idling in traffic, fine on the highway

A gauge that climbs only at idle and recovers once you are moving often points to airflow through the radiator at low speed. At highway speed, air is forced through the radiator; in traffic the cooling fans have to do that job. A fan that is not running, a weak fan motor, a relay or sensor problem, or a radiator blocked with debris can all cause this pattern. Low coolant or air trapped in the system can also contribute.

Please take it seriously. If the gauge reaches the red or you see a warning message, pull over safely and turn the engine off, because overheating can cause expensive engine damage.

Have a shop check that the cooling fans switch on as the engine warms up, pressure test the cooling system for leaks, and inspect the radiator fins. Do not open the radiator or coolant reservoir cap while the engine is hot.