How to Clean Engine Scale?

[DiMargaret]

Here are the steps for cleaning engine scale: 1. After the engine reaches normal operating temperature and is turned off, drain the coolant and add cleaning agent to the cooling system. 2. Restart the engine and let it run at medium speed for 5~10 minutes. During this period, you can also vary the speed to more systematically flush out deposits in the system, then turn off the engine and let it sit for 10~12 hours. 3. Start the engine again, let it run at medium speed for 5~10 minutes, then turn it off and drain the cleaning agent while it's still hot. 4. Repeat the above steps 3~4 times until the discharged cleaning agent is free of contaminants, then reinstall the thermostat.