Inspection Of The Cooling System (Noise Emission Control)

4700 mm 20.02.001
  1. Park the vehicle on a level surface, set the parking brake, and chock the wheels. Open the hood.

    2. Warning: Do not remove or loosen the radiator 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 serious personal injury.

  2. Inspect the SAE pressure/filler cap gaskets. Replace the cap if the gasket shows any signs of deterioration or damage. Install the cap and check to ensure that it seals properly on the surge tank filler neck. Replace the cap if it appears not to seat properly.
  3. There is a valve on the bottom of the SAE pressure/filler cap that opens under vacuum. This prevents components in the cooling/heating systems from collapsing. Inspect the vacuum-relief valve to be sure it is not stuck. Replace the cap if the vacuum-relief valve is stuck.
  4. Check the hoses for possible leaks. Replace any worn, soft, or perforated hoses.
  5. Western Star uses Breeze Constant-Torque hose clamps on the radiator hoses. Check the hose clamps to ensure that they are properly torqued. See Fig.. The tip of the screw must extend about 1/4 inch (6 mm) from the clamp housing, and the washer stacks must be compressed almost flat. Hose clamps lose torque after installation due to "compression set." Breeze Constant-Torque hose clamps will hold enough torque to automatically keep consistent sealing pressure. Due to temperature changes, the screw tip extension may change. The clamp screw may need to be adjusted for individual applications.

    • Screw tip must extend about 1/4 inch (6 mm).

    • Washer stack must be compressed almost flat.

    1. Adjusting Screw Hex

    Fig. 1, Breeze Constant-Torque Hose Clamp

    6. Note: Due to environmental concerns, it is recommended that coolant flushing and the replacement of coolant conditioners and coolant filters be performed by your Western Star dealer.

  6. If the coolant is low, check the engine oil for possible coolant contamination. If the oil is discolored, there may be an internal engine leak, and the unit should be taken to your Western Star dealer to be repaired before the engine is damaged.
  7. Check to see if the front of the radiator, charge air cooler, and oil cooler fins are clogged. Material in the fins will cause the cooling system to overheat. Pressure-wash the radiator to wash out radiator clogging material.
  8. Check the fan belts for wear and tightness. For more information on fan belts, see . If belts are damaged, replace them. If belts are loose, have the proper belt tension set by your Western Star dealer.
  9. Check the fan and fan shroud for damage. A damaged fan or shroud will affect the air flow and can cause heating problems. Have the damaged fan or shroud replaced by your Western Star dealer. If all the previous steps are correct and the engine is overheating, there may be a problem with the fan not operating properly, or the thermostat may be stuck closed. Take your vehicle to a Western Star dealer to have the problem repaired. If there is a tendency for the engine to run cool, the fan may be running continously, or the thermostat may be stuck open. Take the vehicle to a Western Star dealer to have the problem repaired.
Note:
Parent topic: Engine Cooling/Radiator
Document Number: 0000120207
Manual Publication Date: 2024-05-23
Topic Publication Date: 2024-10-31