N40469 Chapter 5 How to drain the coolant circuit Warnings! • Discard the used coolant in a safe place and in accordance with local regulations. • Do not drain the coolant while the engine is still hot and the system is under pressure because dangerous hot coolant can be discharged. 1. Remove the coolant filler cap (figure 2 item 1). 2. Remove the drain plug (figure 3 item 1) from the heat exchanger. 3. After the system has been drained, fit the filler cap and the drain plug. 4. Fasten a label in a suitable place to indicate that the coolant system has been drained. Caution: The closed circuit system cannot be drained completely.
If the coolant is drained for engine preservation purposes or for protection from frost, the coolant system must be filled again with an approved antifreeze mixture. Figure 2 Engines fitted with keel coolers The coolant capacity and the method used to drain the coolant circuit of an engine connected to a keel cooler will vary in different applications. Use the instructions given by the keel cooler manufacturer to drain and renew the engine coolant if a keel cooler is fitted. Figure 3 Page 27