Posted on 9/26/2025
When your temperature gauge starts creeping into the red or steam rises from under the hood, it's a sign that something is wrong. While most drivers know that low coolant or a broken radiator can lead to overheating, some causes are less obvious but just as serious. These hidden issues can sneak up on you, especially if your car runs fine most of the time. If your vehicle keeps running hotter than it should, even after topping off the coolant, you might be dealing with one of these five overlooked problems. 1. A Faulty Radiator Cap That Fails to Hold Pressure The radiator cap does more than just keep coolant inside the system. It is a pressure-release valve that helps maintain the correct pressure in your cooling system. When the cap fails, it may allow coolant to boil at a lower temperature, leading to overheating even if the radiator and thermostat are functioning normally. You might not notice a bad cap until you see coolant bubbling out of the overflow rese ... read more