When the coolant level is low, several noticeable symptoms may occur. The coolant warning light on the dashboard (typically a red thermometer or radiator icon) will illuminate, serving as the most immediate alert. The engine may exhibit abnormal temperature increases or even "boil over," accompanied by bubbling sounds from boiling coolant or steam emission, along with a significant reduction in power output-manifested as sluggish acceleration, rough idling, or abnormally high fuel consumption. Inspection of the radiator or overflow tank will show the fluid level below the MIN mark; if the coolant appears cloudy or discolored, a complete replacement is required. Persistent coolant deficiency in the cooling system accelerates metal component corrosion and rubber seal deterioration; in extreme cases, it may lead to engine seizure or radiator cracking from winter freeze expansion. It is best to check the fluid level monthly and replace the coolant every 2 years or 40,000 kilometres. Frequent fluid loss requires investigation for leaks in components such as the water pump, hoses, or cylinder head gasket.
