What Causes Normal Idle Water Temperature to Rise When Driving?
2 Answers
The reasons for normal idle water temperature rising when driving: 1. Insufficient coolant: Coolant leakage or low coolant level can cause the engine water temperature to rise. If the level is low, first top it up to the appropriate level, then check after a few days to see if the level has dropped significantly. If it has, locate the source of the leak. 2. Faulty radiator fan: When the vehicle is running at high speed, the heat generated cannot be transferred to the coolant in time, affecting heat dissipation. This leads to an increase in coolant temperature, potentially causing overheating. 3. Faulty water pump: Water pump issues include seized bearings and damaged impellers. Seized bearings are relatively rare, while impeller damage, such as cracks or detachment from the pump shaft, is more common. This slows down the coolant circulation, making it easier for the engine to overheat.
I've been driving for over a decade and have encountered several instances where the idle water temperature was normal, but it would skyrocket during highway driving. This is actually quite a common issue, and the main reason is usually that the cooling system can't keep up with the vehicle speed. You'd think that faster airflow from driving would improve cooling, right? But in reality, the opposite happens – it's likely that the radiator grille is clogged with insect remains, poplar fluff, or dust, or that the coolant has degraded from being unchanged for too long. Last time I was on a long trip, I noticed the temperature gauge nearing the red zone, so I pulled over immediately to check. Sure enough, the radiator gaps were packed with dead insects, and cleaning them out with a high-pressure water jet solved the problem. If the cooling fan isn't working properly or the thermostat is stuck, it can also cause this issue. The worst-case scenario is a failed water pump preventing coolant circulation – if this kind of failure isn't fixed promptly, the engine can seize up and be completely ruined.
