Western Star 47X 2020, Руководство по обслуживанию

Страница: 43 / 166

20–00 Safety Precautions
Safety Precautions in this section apply to all
procedures within this group.
DANGER
When working on the vehicle, shut down the en-
gine, set the parking brake, and chock the tires.
Before working under the vehicle, always place
jack stands under the frame rails to ensure the
vehicle cannot drop. Failure to follow these steps
could result in serious personal injury or death.
20–01 Pressure Relief Cap
Check
WARNING
Do not remove or loosen the surge tank cap until
the engine and cooling system have completely
cooled. Use extreme care when removing the cap.
A sudden release of pressure from removing the
cap prior to the system cooling can result in a
surge of scalding coolant that could cause seri-
ous personal injury.
1. Remove the surge tank filler cap first, to relieve
the cooling system pressure, then remove the
SAE cap; see
Fig. 1 .
2. Using a radiator-cap tester, check the pressure
relief cap to see if it maintains pressure to within
10% of the pressure rating marked on the cap. If
it does not, replace the cap. Make sure that the
replacement cap is correctly rated for the cooling
system of the vehicle.
3. There is a second valve in the pressure relief
cap that opens under vacuum. This prevents the
collapse of hoses and other parts that are not
internally supported when the system cools. In-
spect the vacuum-relief valve to be sure it is not
stuck.
4. Make sure that the filler cap seals properly on
the coolant filler neck seat, and that the O-ring is
not cracked or deteriorated. Replace the cap if
the O-ring shows deterioration or damage.
20–02 Radiator Pressure-
Flushing and Coolant
Change
NOTE: For additional instructions on cleaning
and flushing the engine cooling system, see the
applicable engine manufacturer’s maintenance
and operation manual.
1. Park the vehicle on a level surface, shut down
the engine, and set the parking brake. Chock the
tires. Tilt the hood.
2. Place a suitable container under the elbow of the
radiator outlet pipe and the radiator. The con-
tainer should hold at least 60 quarts (59 liters) of
fluid.
WARNING
Do not remove or loosen the surge tank cap until
the engine and cooling system have completely
cooled. Use extreme care when removing the cap.
A sudden release of pressure from removing the
cap prior to the system cooling can result in a
f200865 05/04/2016
1
2
3
1. Surge Tank Filler Cap
2. Surge Tank
3. Pressure Relief Cap (for coolant overflow pressure
relief only)
Fig. 1, Surge Tank
Engine Cooling/Radiator
20
47X and 49X Maintenance Manual, August 2020
20/1