Doosan D20S-5 Operation & Maintenance Manual page 240

Maintenance Section
G430FE 3.0L LPG Engine
3. Open the radiator drain valve. Allow the coolant
to drain into a suitable container.
Drain the recovery bottle.
NOTICE
Hold the drain port when the radiator drain valve is
turned because the tank and the drain port are
separated.
4. After draining the coolant completely, close the
radiator drain valve and the block drain plug, fill
the engine and the radiator full with a radiator
cleaner, and clean the engine and the radiator.
5. Start and run the engine for 30 minutes.
6. Stop the engine and drain the cleaning solution
into a suitable container.
7. Flush the system with clean water, until draining
water is clear.
8. Close the drain valve and install the block drain
plug. Fill coolant to top of the filler neck.
9. Start and run the engine to stabilize the coolant
level. See topic, "Coolant Level – Check" in
"Every 10 Service hours or Daily".
Inject the coolant additionally into below specific
port of G424I(E) engine besides the radiator if
needs more coolant while clean & change the
cooling system.
10. Remove the indicated coolant hose above
picture and then, add the coolant to hose as
much as needed.
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NOTICE
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