Section 05: COOLING SYSTEM
PA1562
12
6. DRAINING COOLING SYSTEM
Use the following procedures to drain the
cooling system partially or completely.
To drain engine and related components:
1. Stop engine and allow engine to cool. Close
both heater line shutoff valves.
On X3- 45 coaches, the valves are located in the
engine compartment. One is located under the
cooling fan right angle gearbox; another valve is
on the L.H. side of the engine compartment in
front of the radiator (Fig. 14).
NOTE
Refer to section 22 under "Preheating
System" for information about preheater
access and heater line shutoff valve.
WARNING
Before proceeding with the following steps,
make sure the coolant has cooled down. The
sudden release of pressure from a heated
cooling system can result in loss of coolant
and possible personal injury (scalding) from
the hot liquid.
2. Close the shut-off valves on the coolant filter
mounting head (if applicable) and remove
filter (perform only if filter as to be replaced).
3. Open the shut-off valves on the coolant filter
mounting head (if applicable) and drain the
coolant into a suitable container. Close the
shut-off valves.
4. Unscrew the surge tank pressure cap
counterclockwise, ¼ turn to let air enter the
system and permit the coolant to drain
completely from system.
5. Unscrew the water pump housing inlet line
drain plug (Fig. 15) plus the transmission oil
cooler delivery line drain plug. Drain the
coolant into an approved container.
NOTE
On Volvo D13 engine, the regular drain plugs
are replaced by quick connect fittings to ease
draining and filling of coolant system.
6. Open drain cock at bottom of thermostat
housing to drain the coolant trapped above
the thermostats (Fig. 11).
7. Open the radiator drain cock.
FIGURE 15: WATER PUMP DRAIN PLUG 05093
8. Remove the transmission oil cooler. Drain,
flush and inspect. Refer to Section 7,
“TRANSMISSION” for oil cooler
maintenance or preventive replacement.
CAUTION
Drain water pump completely before extended
storage to avoid possible water pump
damage.
If freezing weather is anticipated and the
engine is not protected with antifreeze, drain
the cooling system completely when vehicle is
not in use. Trapped water in the cylinder
block, radiator or other components may
freeze and expand resulting in damages.
Leave the drain plugs open until the cooling
system can be filled with coolant fluid. Do not
run engine with cooling system empty.
To drain the entire system, do the previous
steps while maintaining the shutoff valves in the
open position; then follow the procedure under
“Draining Heating System” in Section 22.
7. FILLING COOLING SYSTEM
If only the engine and related components were
drained, maintain the two heater line shutoff
valves in their closed position, then proceed as
follows:
1. Close all drain cocks. Reinstall the drain
plugs with new seals. Refer to draining
procedure for the location of draining points.
2. Open the shut-off valves on the coolant filter
mounting head (if applicable).
3. Refill cooling system from the surge tank
filler cap inlet with the recommended
ethylene glycol-based antifreeze and water
solution of the required concentration.
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