You can use various methods and equipment to flush the cooling system. If special equipment is used (such as a back flusher) follow the manufacturer's instructions. However, always remove the thermostat before flushing the system.
In order to remove hardened scale from the radiator, a direct chemical action is needed.
There are various types of flushing compounds commercially available. Obtain these from a reliable source.
Most compounds attack metals and these should not remain in the engine for more than a few minutes. Use a neutralizer in the cooling system immediately after using a de-scaling solvent. For extremely hard, stubborn coatings, such as lime scale, use a stronger solution. The corrosive action of a stronger solution affects the thin metals of the radiator, reducing the operating life of the radiator. Because of this, flushing and rinsing the radiator is required.
After you use the solvent and the neutralizer, and after you flush the system, perform the following steps: