At what engine coolant temperature can the car's heater be turned on?
3 Answers
The car's heater can be turned on when the engine coolant temperature reaches 80°C to 90°C. The normal operating temperature of a car engine is generally between 80°C and 90°C, while some high-performance engines may operate at temperatures above 100°C. Since the heater's warmth comes from the engine coolant, turning on the heater too early will slow down the coolant's warming process and prolong the warm-up time. After a cold start, the temperature gauge typically begins to show readings around 60°C, and you may feel warm air from the vents. However, for engine protection, it is recommended to wait until the coolant temperature reaches 80°C to 90°C before turning on the heater. Before the engine reaches its operating temperature, the fuel-air mixture's poor atomization may increase fuel injection, leading to carbon deposits. Additionally, when the heater is turned on, the coolant from the heater core will flow back into the engine block, further extending the engine's warm-up time.
As an experienced driver frequently driving in the north, I've noticed that turning on the heater immediately after starting the car in winter only blows cold air. This is because the heater relies on the engine's heat, and it won't produce warm air until the coolant temperature rises. I wait until the coolant temperature reaches around 90 degrees before turning on the heater, and the effect is much better. The normal operating temperature for coolant is generally between 80-90 degrees Celsius. When the temperature gauge on the dashboard reaches the midpoint, that's the time to press the air conditioning heater button. Turning it on too early might slow down the engine's warming process and affect fuel consumption. I'm also in the habit of preheating for a few minutes to stabilize the interior temperature, especially during long drives in sub-zero weather—it's both safer and more comfortable. In short, a little patience until the coolant warms up goes a long way.
As a safety-conscious driver, I fully understand the importance of coolant temperature when using the heater. While driving, I never turn on the heater until the coolant temperature rises above 80 degrees Celsius, otherwise the windshield tends to fog up, impairing visibility. Generally, it's safe when the coolant reaches 70-80°C, as the air blown by the heater becomes warm. In cold seasons after starting the car, I always wait until the dashboard shows the temperature has risen - this usually takes just a few minutes - before activating the heating system. This approach not only ensures warmth inside the car but also prevents prematurely increasing the engine's workload. Rushing this process can cause problems - a friend of mine experienced this firsthand.
