Cooling System - Overheat Condition/Coolant Loss
No: 26/03/05/NASRef: 26/01/03/NAS
Issue: 1
Date: March 07, 2005
Engine Overheating and Coolant Loss
AFFECTED VEHICLE RANGE:
Freelander (LN) All
SITUATION:
VARIOUS CAUSES FOR ENGINE OVERHEATING AND COOLANT LOSS
The customer may complain of high engine temperature indication or possibly of coolant loss. There are a number of potential causes for such a complaint:
Overheating without apparent coolant loss
^ Fan controller inoperative or not operating correctly (Refer to TIB 26/01/03/NAS)
^ Twisted heater hoses
^ Faulty thermostat
^ Leaks in the expansion tank
^ Coolant flow restriction through the by-pass port in the thermostat housing, caused by a moulding flaw in the housing
^ Poor coolant system bleed
Overheating with coolant loss
^ Poor sealing of the coolant expansion tank cap
^ Leaking or detached cylinder block heater stub pipe
^ Poor coolant system bleed (observed level fluctuation and apparent coolant loss)
RESOLUTION:
INVESTIGATE CAUSE AND RECTIFY
When complains relating to overheating are confirmed, investigate and test the system. Perform the tasks outlined for each symptom as outlined in this bulletin.
PARTS INFORMATION
DDW WARRANTY CLAIMS:
DDW requires the use of causal part numbers. Labor only claims must show the causal part number with a quantity of zero.
REPAIR PROCEDURE
PRELIMINARY COOLING SYSTEM DIAGNOSTIC CHECKS
1. Refer to Technical Information Bulletin 26/01/03/NAS and verify that the cooling fans are operating correctly.
2. Refer to GTR section 12.30.50 and remove the engine acoustic cover.
WARNING::
Injury such as scalding could be caused by escaping steam or coolant. Removal of heater hoses or the filler cap from the coolant expansion tank while the cooling system is hot can result in the release of steam or hot coolant.
3. Install coolant system pressure tester (LRA-26-001) to expansion tank and pressurize system to 15 psi.
4. Observe all hose connections and engine block stub pipe for visible leakage.
5. Release test pressure.
6. Check the heater coolant hoses between the bulkhead and the rear of the engine.
^ Verify that there is no leakage at the hose connections.
^ Ensure the hoses are in their correct positions and free from twists or kinks.
7. If either heater hose is incorrectly installed, twisted or kinked, perform the following:
^ Position a container to collect spilled coolant.
^ Release hose clamps and disconnect relevant hose(s) from heater.
^ Straighten hose(s) as required and reconnect.
^ Secure straightened hose(s) with clamps.
^ Top-up the coolant system.
8. Start and run the engine until normal operating temperature is reached.
NOTE:
Hose temperature is an indication of correct thermostat operation. If the radiator bottom hose is warm/hot, the thermostat is operating correctly. If the radiator bottom hose remains cold, the thermostat is not operating correctly.
WARNING:
Checking that the bottom hose is hot while the engine and/or cooling fans are running could result in personal injury.
9. Monitor the bottom radiator hose using a non-contact thermometer (Raytek MiniTemp or similar) to determine that the hose becomes hot and the thermostat has opened. (Figure 1)
10. Increase the engine speed to between 2000 and 2500 RPM using an assistant to maintain this engine speed.
11. Monitor the coolant level:
^ If the coolant level rises significantly, but the flow from the bleed port is reversed, (i.e. flowing OUT of the expansion tank), the thermostat assembly is restricted.
^ If the coolant level falls, but the flow from the bleed port is constant, the thermostat is NOT restricted, but the cooling system still contains some trapped air.
^ If the coolant level rises slowly, and the flow from the bleed port is constant and the thermostat is not restricted, the expansion tank is not sealing fully.
12. Visually inspect the heater stub pipe located in the rear of the cylinder block for leaks and ensure the stub pipe is secure.
13. Turn off the engine.
CORRECTIVE ACTION FOR OBSERVED SYMPTOMS
WARNING:
Performing work while the cooling system is hot could release dangerously hot steam or fluid.
1. When inspection and coolant monitoring is completed, allow the engine and coolant to cool.
2. If the bottom radiator hose was cold and the coolant level increased significantly in the reservoir, but the flow from the bleed port is reversed, refer to GTR section 26.45.01 and replace the thermostat (PEM000030).
3. If the heater stub pipe is loose or a leak was observed, replace the pipe as follows:
^ Position the vehicle on a lift.
^ Disconnect the battery ground lead.
^ Refer to GTR section 26.10.01 and drain the coolant.
^ Refer to GTR section 30.15.16 and remove the Right Hand exhaust manifold.
^ If fitted, move aside heat protection sleeve from the heater stub pipe coolant hose.
^ Release hose clamp and disconnect the coolant hose from the heater stub pipe.
^ Position a 13.5 mm (0.531") diameter bar (for example a socket or extension bar) inside of the heater stub pipe (Figure 2).
^ Position and clamp Vise-Grip(R) pliers to the exterior of the heater stub pipe.
^ Using a pair of pry bars carefully remove the stub pipe from cylinder block (Figure 3).
^ Clean all loose debris from the block stub pipe bore.
^ Clean the new heater stub pipe and the stub pipe bore in the cylinder block with alcohol.
^ Apply high strength retainer Loctite(R) 648 to the circumference of the replacement heater stub pipe (LCP100180), approximately 5 mm (3/16 inch) from the unpainted end.
CAUTION:
Ensure that the new pipe is pushed fully into position so that the new pipe is not damaged and that an even bead of sealant remains around the joint.
^ Carefully fit the new heater stub pipe to the cylinder block and gently tap it in to place using a socket or similar tool to protect the stub pipe. (Figure 4).
^ Remove excess high strength retainer from the cylinder block.
^ Connect the coolant hose to the heater stub pipe and secure with the removed clamp.
^ If installed, position the heat protection sleeve to the coolant hose.
^ Refer to GTR section 30.15.16 and install the RH exhaust manifold.
^ Lower the vehicle.
^ Connect the battery ground lead.
^ Refer to GTR section 26.10.01 and refill the system with coolant.
^ Using the pressure tester, verify there are no leaks around the heater stub pipe.
NOTE:
The expansion tank my have minor "crazing" or surface cracks. These are an expected condition and are not a reason to replace the tank. Large cracks with evidence of coolant seepage do require corrective action.
4. If the coolant monitoring indicated that the expansion tank is not sealing fully, perform the following:
^ If the new specification ratcheting cap is installed, perform the following:
> Verify that the cap is tightened completely by twisting until the ratchet feature is activated.
> If the cap was properly tightened, pressure test the cap to 15 psi.
> If the cap fails the pressure test, replace the cap.
^ If the early style tank and cap are installed, refer to GTR section 26.15.01 and replace the expansion tank assembly with the new specification tank and cap (PCF000012 and PCD00090).
5. If the coolant monitoring indicated the need to bleed the system or the work performed in this TIB require the bleed process be performed, refer to GTR section 26.10.01, steps 5 to 21, and bleed the cooling system.
6. When all work is completed, install the acoustic cover.