Measuring pressure in the cooling system 4.4L (Discovery 3)

NOTE: The following procedure allows you to pressure test the cooling system for leaks. Step 1 checks the expansion tank cap seal and expansion tank cap for leaks. Step 2 tests the entire cooling system.

NOTE: It will be necessary to use the Cooling System Test Kit part number LR-218, which is available through the Equipment Supply Program.

1. Check the coolant hoses for cracks and deformation and ensure that the connections are tight.

2.

CAUTION: Because leaking steam or coolant can cause burns, allow the vehicle's cooling system to cool before attempting this procedure.

Disconnect the expansion tank outlet hose. Release the clamp.

3. Install the T-piece (included in the cooling system test kit) between the expansion tank and the outlet hose. Secure it with two clamps.

4. Install the coolant injection pump assembly. Connect the T-piece.



5. Create pressure in the cooling system.

• Slowly increase the pressure in the cooling system to 1.0 bar (100 kPa).
• Check that after 30 s the pressure is greater than 0.9 bar (90 kPa).
• While checking for pressure loss, check for hissing sounds coming from the expansion tank cap.

6.

NOTE: If the expansion tank cap is found to be leaking, replace the cap.

Relieve pressure in the cooling system.

• Disconnect the T-piece.
• Connect the expansion tank outlet hose.
• Secure the clamp.

7.

CAUTION: Because leaking steam or coolant can cause burns, allow the vehicle's cooling system to cool before attempting this procedure.

Remove the expansion tank cap.

8.

NOTE: This adapter is included in the cooling system test kit.

Install the K83 adapter onto the expansion tank.

• Clean the contact surfaces of the parts.
• Lubricate the seal.

9. Install the coolant injection pump assembly.

• Slowly increase the pressure in the cooling system to 1.5 bar (150 kPa) and check it after 5 minutes. A slight decrease in pressure of about 0.15 bar (15 kPa) in the first minute is normal, as the air in the expansion tank cools down.
• A continued drop in pressure below the initial tolerance indicates a coolant leak.

10. Reduce the pressure in the system and remove the injection pump and pressure gauge. Install the expansion tank cap.