Radiator Pressure-Flushing and Coolant Change

p3 mm 20.02

    Note: For additional instructions on cleaning and flushing the engine cooling system, see the applicable engine manufacturer's maintenance and operation manual.

  1. Apply the vehicle parking brakes, then chock the tires. Tilt the hood.
  2. Place a suitable container under the elbow of the radiator outlet pipe and the radiator. The container should hold at least 60 quarts (59 liters) of fluid.

    3. 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 serious personal injury.

  3. Remove the surge tank cap.
  4. Remove the drain plugs at the radiator side tank and at the lower radiator outlet pipe elbow, if equipped. See Fig . Allow the coolant to drain.

    Note: Cummins engine shown

    1. Coolant Drain Plug

    Fig. 1, Coolant Drain Plug Location

  5. Disconnect the radiator upper and lower hoses, and install the surge tank cap and the radiator tank drain plug. Attach the flushing gun nozzle to the radiator at the lower radiator hose opening. Run the water until the radiator is full.

    6. Caution: When flushing the radiator, do not apply more than 15 psi (100 kPa) air pressure. Excessive pressure can damage the radiator.

  6. Gradually, apply up to 15 psi (100 kPa) air pressure to help dislodge sediment that has built up in the radiator core.
  7. Shut off the air at the pressure gun nozzle and allow the radiator to refill with water.
  8. Repeat the previous two steps until clean water flows from the radiator.
  9. Remove the radiator drain plug and allow the radiator to drain. Install and tighten the drain plug after the radiator has been drained. Do not overtighten.
  10. Connect the hoses. Your hose clamps can be either T-bolt clamps (see Fig.) or Breeze Constant-Torque clamps (see Fig.).
    When working with T-bolt hose clamps, tighten the clamps 55 lbf·in (620 N·cm). These clamps are now standard on hoses with an in diameter greater than 2 inches (51 mm).
    When installing Breeze Constant-Torque hose clamps, the clamps must be tightened to the correct torque. The screw tip of the clamp must extend about 1/4 inch (6 mm) from the clamp housing, and the Belleville washer stacks must be collapsed almost flat. Use a torque wrench to install these clamps correctly. The correct installation torque is as follows:
    For Breeze Constant-Torque clamps with a 5/16-inch tightening screw hex: 55 lbf·in (620 N·cm).
    For Breeze Constant-Torque clamps with a 3/8-inch tightening screw hex: 90 lbf·in (1020 N·cm).

    Fig. 2, T-Bolt Type Hose Clamp

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

    • Belleville washers must collapse almost flat.

    1. Tightening Screw Hex

    Fig. 3, Breeze Constant-Torque Hose Clamp Installation

    11. Note: All hose clamps will lose torque after installation due to "compression set." However, when correctly installed, Breeze Constant-Torque clamps will hold enough torque to automatically adjust and keep consistent sealing pressure. During vehicle operation and shutdown, the screw tip may adjust according to temperature and pressure changes. The torque may need to be adjusted for individual applications.

  11. Place a pan under the coolant filter to catch engine coolant.
  12. Remove the coolant filter with a strap or chain wrench. Install a new coolant filter and tighten.
  13. Fill the cooling system with new coolant. The cooling system is filled when the coolant level reaches the MAX line on the surge tank. Refer to the engine manufacturer's service literature for specific coolant information.
  14. Replace the surge tank cap(s).
  15. Return the hood to the operating position.
  16. Start the engine and turn on the cab heater. Allow the engine to warm up to normal operating temperature. Check the radiator and hoses for leaks. Repair as needed.
  17. Shut off the engine, then check the coolant level in the surge tank. Add coolant if the level isn't at the MAX line on the surge tank.
Note:
Parent topic: Engine Cooling/Radiator
Document Number: 0000110987
Manual Publication Date: 2024-05-15
Topic Publication Date: 2024-11-22