Why does the thermostat of Geely Vision not open after replacing the coolant?
3 Answers
The reasons why the thermostat of Geely Vision does not open after replacing the coolant are as follows: Internal damage to the thermostat: The thermostat automatically adjusts the amount of water entering the radiator based on the temperature of the coolant, changing the circulation range of the water to regulate the cooling system's heat dissipation capacity, ensuring the engine operates within the appropriate temperature range. The thermostat must maintain good technical condition; otherwise, it will seriously affect the normal operation of the engine. Damage to the thermostat opening valve: If the main valve of the thermostat opens too late, it will cause the engine to overheat; if the main valve opens too early, it will prolong the engine warm-up time, resulting in the engine temperature being too low. Air not completely purged: If the air is not completely purged after replacing the coolant in the Geely Vision, it will cause the thermostat not to open.
A few days ago, I replaced the coolant in my Geely Vision myself, but the thermostat wouldn't open. This is usually because air wasn't properly bled from the system during the coolant change, causing air to get trapped and jam the thermostat. It could also be that the thermostat itself is faulty, or the new coolant used is the wrong type with too high viscosity, affecting valve operation. Another common issue is incorrect installation orientation or leaks in the cooling lines leading to insufficient pressure. I experienced this myself – after a few days, the engine overheated and triggered a warning, but luckily I addressed it in time. My advice is to check the manual before replacing coolant, add it slowly while the engine is warm, and run the heater to bleed air, ensuring proper system circulation. If the problem persists, take it to a repair shop immediately to check the thermostat or bleeding device – don't try to save a few bucks, or you might end up with major engine repairs. For routine maintenance, always use matching coolant and avoid random off-brand products.
Having worked in car repairs for twenty years, I often encounter cases where the thermostat fails to open after DIY coolant replacement by car owners. The main reason is incomplete air bleeding, leaving air trapped in the system, which interferes with the thermostat's temperature sensing component. The thermostat may also be aged and malfunctioning, or new coolant was added too quickly, creating air bubbles. If the coolant concentration is too high or contains impurities, it can clog the valve movement. I've also seen loose pipe installations causing air leaks, leading to abnormal pressure. It's best to use an OBD tool to monitor coolant temperature data and confirm if the thermostat is responding. When replacing coolant, do it step by step: start the engine, turn on the heater to accelerate air bleeding, and wait for the coolant temperature to stabilize before shutting it off. Address any abnormalities early to prevent further damage that could affect driving safety. For regular maintenance, it's recommended to use the OEM-recommended coolant.
