Abstract: Using techniques like corrosion weight loss test, electrochemical testing, and electron scanning microscopy (SEM), the long-term corrosion behavior of aluminum alloy 3A21 in glycol coolant at temperatures ranging from 5-70 ℃ was examined. It was investigated how temperature affected the way aluminum alloy 3A21 corroded in ethylene glycol coolant. The results show that the average corrosion rate of 3A21 aluminum alloy increased steadily as the temperature in the glycol coolant rose within the experimental temperature range. With a minor amount of localized corrosion present, the surface corrosion morphology was primarily uniform. The logarithm of the average corrosion rate was linearly proportional to the reciprocal of the absolute test temperature during the 56-98 day test period. There was an Arrhenius relationship between immersion temperature and the steady corrosion rate of aluminum alloy 3A21 in glycol coolant.