Scale Removal

NOTE: To remove the hardened scale, a direct chemical action is necessary.

1. A flushing compound at the specified rate of 30 grams per liter (4 oz. per gallon) of radiator capacity, should be added to the coolant water in the form of a dissolved solution while the engine is running.
2. Operate the engine for 15 minutes, then drain and flush the system with clean water.
^ There are various types of flushing compounds commercially available, but they should be obtained from a reliable source. Most compounds attack metals and should not remain in the engine for more than a few minutes. Use a neutralizer in the cooling system immediately after a descaling solvent is used.
^ For extremely hard, stubborn coatings, such as lime scale, use a stronger solution. The corrosive action of a stronger solution will affect the thin metals of the radiator, thereby reducing its operating life. A complete flushing and rinsing is mandatory.
3. After the solvent and neutralizer have been used and the cooling system is flushed, drain the entire system and fill it with clean, soft water plus a rust inhibitor or high boiling type antifreeze. After filling the cooling system, check for radiator, hose and engine coolant leaks.