How to Bleed the System for High Engine Temperature?
3 Answers
Here are the specific methods for bleeding the system when the engine temperature is too high: 1. If the temperature is excessively high or the temperature warning light keeps flashing, stop the vehicle to check whether the coolant level in the radiator is normal and inspect the radiator, hoses, and all connections for leaks. If no abnormalities are found during the visual inspection, refill the coolant as required and continue driving. If the temperature remains high after driving for a while and the coolant level drops upon stopping to check, this is likely due to a sand hole or perforation in the cylinder block's water jacket causing leakage. Upon discovering this issue, repairs should be carried out. 2. When the engine temperature is too high, you can touch the upper and lower radiator hoses to determine the fault. If there is a significant temperature difference between the two hoses, it can be concluded that the thermostat is not functioning. 3. If there is air in the cooling system, it can create an airlock, hindering proper coolant circulation and leading to high engine temperature. Run the engine at high speed and gently loosen the radiator cap until gas begins to escape. Some coolant may escape with the gas. Repeat this process several times until all the gas is released. After resolving the issue, promptly replenish the coolant. 4. If the vehicle has been driven on dirt roads or muddy sections for an extended period, debris may accumulate on the radiator, which over time can impair cooling efficiency and cause high water temperature. First, use compressed air to blow out the radiator grille, then rinse it with a water hose.
That day when I was driving long-distance, I noticed the temperature gauge was about to max out, so I quickly pulled over, turned off the engine, and waited for it to cool down. The gurgling sound in the coolant reservoir definitely meant there was air trapped inside. When opening the engine hood, don’t immediately remove the cap—use a thick cloth to slowly unscrew the coolant filler cap. Park the car on level ground and start the engine, keeping the RPM around 2000. You’ll see bubbles forming in the coolant, which means the air is being purged. At the same time, squeeze the upper and lower radiator hoses to help with circulation. Once the bubbles reduce, quickly top up with dedicated coolant to the standard level. Don’t forget to check the water pump and thermostat. It’s best to have two people cooperate during this process—one to press the accelerator and the other to observe. After purging the air, test-drive for half an hour, keeping an eye on the temperature gauge to avoid the red zone. Older cars are especially prone to this issue.
Dealing with high water temperature and bleeding the system is actually not difficult. I prefer to operate safely when the engine is cold. First, locate the coolant expansion tank and open the cap. Start the engine and let the water temperature rise until the fan kicks in. Then, squeeze the hose to promote circulation and expel air. You'll know it's working when the coolant level drops and bubbles emerge. At this point, top up the coolant to the middle mark. Pay special attention not to mix coolants of different colors. After completing these steps, I also checked the radiator and the sealing of the tank cap. Models equipped with dedicated bleed screws make the process even more convenient. Regular maintenance includes periodically replacing the coolant. Remember to wear gloves for protection throughout the process. If bleeding doesn't improve the situation, it might indicate a cylinder head gasket issue. Handling it yourself saves much more time than waiting for a tow truck.
