Will a broken radiator cap cause overheating?
2 Answers
A damaged radiator cap can cause overheating. The effects of a damaged car radiator cap include: 1. Coolant may spray out from the radiator cap; 2. After the coolant sprays out, the flow rate and pressure of the coolant entering the engine will decrease; 3. Due to the reduced coolant flow, the engine's heat cannot be dissipated by the coolant, leading to engine overheating. This can cause the engine to "boil over," resulting in certain degrees of damage to the engine. The radiator cap has three main functions: 1. Sealing to prevent coolant leakage. 2. When the coolant temperature rises and the pressure inside the radiator increases to a certain level, the radiator cap automatically opens the pressure relief valve, allowing excess coolant (due to thermal expansion) to flow into the auxiliary reservoir. 3. When the coolant temperature drops, the radiator forms a vacuum due to the coolant's contraction. At this point, the radiator cap automatically opens the return valve, allowing the supplementary coolant from the auxiliary reservoir to flow back into the radiator.
A faulty radiator cap can indeed easily cause engine overheating. I experienced this issue when driving an older car—the temperature gauge kept climbing, and upon inspection, it turned out the radiator cap's seal was compromised, releasing all the pressure and allowing the coolant to boil inside the radiator. Normally, the radiator cap acts like a pressure cooker lid, raising the boiling point and preventing the coolant from boiling over. Once the cap fails and pressure is lost, the boiling point drops, causing the engine temperature to spike during long drives. Short trips might be manageable, but prolonged neglect can damage the engine, risking cylinder head warping or scale buildup. I caught it early and fixed the problem by replacing the cap. It's wise to regularly check the cap's seal and pressure spring—replace them if they show signs of aging to avoid major issues.
