A common year has 365 days and a leap year 366 days, with the extra, or intercalary, day designated as February 29. A leap year occurs every four years to help synchronize the calendar year with the solar year, or the length of time it takes the earth to complete its orbit about the sun, which is about 365¼ days.
When the coolant temp is low it closes and allows the engine to warm to the designed temperature.The are three most likely causes. A defective thermostat that stays open. This allows the coolant to flow thru the radiator and actually overcools the engine. It could also be a defective gauge ot sensor.