Bleeding the cooling system on a Honda Acty—whether HA3/HA4 (E05A) or HA6/HA7 (E07Z)—is essential after replacing the radiator, thermostat, or coolant, as air pockets can cause overheating or erratic temperature readings. To do it properly, start with a completely cool engine, and raise the front of the vehicle slightly if possible to help air escape. Open the radiator cap and fill it slowly with Honda-compatible 50/50 coolant until full. Set the heater to full hot, and start the engine, allowing it to idle with the cap off. As the engine warms, keep an eye on the coolant level and watch for air bubbles escaping—this is a sign that trapped air is being purged. Periodically squeeze the upper and lower radiator hoses to help force air out of tight spots. Once the thermostat opens (after a few minutes), the coolant level may drop—top it off as needed. When bubbles stop and the coolant stabilizes near the top, reinstall the radiator cap securely. Let the engine run until it reaches normal operating temperature and confirm the heater is blowing hot air. After the engine cools completely, recheck the coolant level in both the radiator and overflow tank, topping off if necessary. This process helps ensure your Acty’s cooling system is fully pressurized and free of air, preventing overheating and keeping the engine running at safe temperatures.