What's the reason for the thermostat not opening?

[VeraDella]

The reasons for the thermostat not opening: The water temperature is not high enough; The water channel is blocked; The radiator is frozen. Here are some introductions about the thermostat: 1. Water with excessively high temperature and pressure cannot be pressed into the water tank by opening the radiator cap, which may cause damage to the water jacket of the small circulation system. 2. The main type of thermostat used is the wax thermostat. When the cooling temperature is below the specified value, the refined paraffin in the temperature sensing body of the thermostat is in a solid state, and the thermostat valve closes the channel between the engine and the radiator under the action of the spring. The coolant returns to the engine through the water pump, performing a small circulation within the engine.

[BrynleeRose]

When the thermostat fails to open, I suspect your car's coolant temperature might skyrocket, which is a pretty common issue. The thermostat acts like a valve, specifically managing the engine's heat circulation, but it can easily get stuck due to impurities in the coolant—especially if you haven't changed the coolant for a long time, as scale buildup can jam it completely. Also, if the temperature sensor is faulty, it won't respond to changes in coolant temperature. Additionally, aging or broken spring components can prevent the valve from moving. I once experienced this with an old car—the temperature gauge suddenly shot into the red, giving me quite a scare. In such cases, the risk of engine overheating is high, and prolonged exposure can lead to internal engine damage, potentially requiring major repairs. My advice is to first check if the coolant level is adequate, then start the car and wait for the temperature to rise. Feel the upper and lower radiator hoses for temperature differences: if one is hot and the other cold, the thermostat is likely stuck. Fixing it isn't too hard—just head to a professional shop ASAP to replace it, and avoid DIY disassembly to prevent incorrect installation. For prevention, I recommend changing the coolant and filter every two years or so to keep the system clean.

[PiperAnn]

I've experienced the thermostat failing to open a few times while driving, and it was quite a hassle each time. Initially, the water temperature wasn't high, but during long-distance drives, the temperature gauge would skyrocket. It turned out the thermostat was stuck due to rust or dirt buildup. This small component is designed to regulate heat flow, but over time, dirt accumulation can cause it to seize up. I've also encountered issues like insufficient coolant or air bubbles blocking the system, which can easily lead to thermostat failure—like that time I forgot to do regular checks. Another sign is abnormal engine temperature fluctuations, where the thermostat responds poorly, indicating potential early issues—not a good sign. I usually stop the car, wait for it to cool down, and check if the valve can be moved manually, but it's best not to force it. If it won't open, the consequences are severe: engine overheating can damage the head gasket, leading to costly repairs. Since then, I've made it a habit to change the coolant more frequently to reduce impurity buildup. The key is to fix it promptly and avoid risking further damage by continuing to drive.

[OmarLynn]

There are many reasons why a thermostat fails to open, and I'd say 80% of the time it's due to a stuck or malfunctioning valve. Sticking can be caused by dirt buildup or rust, while malfunction often occurs when the temperature sensing element is faulty. After starting the car, observe the coolant temperature gauge - if the temperature remains abnormally high without dropping, the thermostat may not be opening properly. At this point, it's crucial to check the coolant level and freshness, as old fluid with excessive impurities can easily cause blockages. Additionally, prolonged vehicle use leads to component wear; loose springs or connection points can also affect performance. My usual recommendation for simple self-check: After turning off and cooling the engine, manually test the valve's movement for smooth operation. If stuck, promptly take it for repair and replacement. This prevents engine damage from overheating. Regular maintenance is the best preventive measure.

[DelKinsley]

The thermostat is stuck and won't open. I've observed this several times, and the root cause is often due to poor maintenance. When the coolant becomes dirty and forms deposits, it sticks to the valve, jamming it tightly; or the temperature sensor fails to respond to the engine's temperature rise. Over time, neglecting to replace the coolant or filter leads to a buildup of impurities in the system, making the thermostat prone to failure. In my daily driving, I've noticed that this affects engine efficiency, causes unstable temperature control, and accelerates wear. In severe cases, the water temperature can skyrocket, leading to overheating and the car breaking down halfway. To address this, first check if it's a coolant issue—top it up if it's low. If that doesn't work, inspect the water pump and the cooling system for blockages. To prevent such issues, I've developed a habit of checking the cooling system every six months.