Radiator Pressure Flush and Coolant Change
Note: For additional instructions on cleaning and flushing the cooling system, see the engine manufacturer's maintenance and operation manual.
For Cummins engine service literature, refer to the Cummins Online website at https://www.cummins.com/support/manuals or scan the QR code. See Fig.. For Detroit™ engine service literature, refer to the Detroit Diesel link on the DTNA TechLit website https://www.dtnatechlit.com/portal-public or scan the QR code. See Fig..
Fig. 1, Cummins QR Code
Fig. 2, TechLit QR Code
- Place a large container under the radiator.
- Remove the surge tank cap.
- Open the petcock at the bottom of the radiator to drain the engine coolant.
- Disconnect the radiator inlet and outlet hose connections.
- Attach a flushing gun nozzle to the radiator outlet.
- Add water to the radiator until it is full.
- Add water to the radiator until it is full.
- Drain the radiator, then flush the radiator until clean water flows from the radiator. Remove the flushing gun.
- Close the petcock.
- Using clamps, connect the hoses to the radiator. Torque the clamps 33 to 38 lbf·in (370 to 430 N·cm).
- Fill the radiator with coolant. Use a 50/50 mixture of
antifreeze and water. Refer to the coolant label on the vehicle or
the engine manufacturer’s service literature for approved coolants.
Coolant used must be compatible with the engine manufacturer’s
coolant specifications.
Table 1, Coolant Capacities
Engine Make and Model
Coolant Volume: quarts (liters)
Cummins ISB†
30.5 (28.9)
Detroit™ DD5 (5.1L)‡
30.5 (28.9)
MBE900 (6.4L)
37 (35)
Table 1, Coolant Capacities
† For Cummins engine service literature, refer to the Cummins Online website at .
‡ For Detroit™ engine service literature, refer to the Detroit Diesel link on the DTNA TechLit website .
Important: If the heater circuit valves were closed earlier, open the valves now.
Important: If the vehicle is equipped with heater circuit valves, the valves should be closed to prevent the loss of coolant.
Important: On vehicles with EPA07 compliant engines, the coolant capacity varies depending on the engine and accessory installation. After servicing the cooling system, always verify that the coolant level is between the MIN and MAX lines on the surge tank.