Why does the coolant warning light come on and then go off?
2 Answers
Car coolant warning light comes on and then returns to normal because the coolant is slightly low. When the vehicle is in motion, the liquid level fluctuates, causing intermittent warning signals. You should promptly go to a repair station to replenish the coolant. Below is detailed information about car engine coolant: Overview: Coolant, also known as antifreeze, radiator fluid, etc. Its main function is to protect the engine for normal and good operation, circulating in the engine radiator to provide antifreeze, anti-boil, anti-rust, and anti-corrosion effects. Others: Generally, the color of antifreeze is red or green to observe any leaks. Engine coolant is commonly a glycol-water solution.
I often encounter the coolant warning light coming on briefly while driving. This is mostly due to air bubbles trapped in the cooling system, especially during cold starts when the bubbles cause a temporary drop in fluid level, triggering the warning. Once the car warms up and the bubbles are expelled, the warning disappears. Alternatively, parking on uneven ground can cause the coolant level sensor to misjudge due to fluid tilt—straightening the car body should resolve this. Another possibility is a minor leak, such as slight dripping from a radiator hose connection, where the fluid level drops to the critical point, triggering the warning before rising again. I recommend first checking whether the coolant reservoir level is between the Min and Max marks, especially when the engine is cold for a more accurate reading. Regularly inspect for any signs of moisture, as small leaks can accumulate over time and damage the engine. If this happens frequently, it's best to visit a shop for a pressure test to check the radiator and hoses. Don’t overlook these details to keep your car in good health.