Cooling System - Engine Overheating Condition
No.: LTB00045Issue: 1
Date: May 25, 2007
SECTION: 303-03
Engine Overheating Diagnostic Aid
AFFECTED VEHICLE RANGE:
Range Rover (LM) VIN: 6A198058 to 7A241928
CONDITION SUMMARY:
DIAGNOSIS OF OVERHEATING COMPLAINT REQUIRED
Situation:
A customer may report a concern that the temperature gauge indicates the engine is overheating. There are a number of potential causes that could lead to the above complaint.
Action:
This bulletin provides diagnosis information for the above concern which should be completed before changing the thermostat. Should a customer express concern regarding the above, refer to the Service Tips detailed in this bulletin.
PARTS:
PGF500340.........Upper right quadrant fan cowl Qty 1
WARRANTY:
NOTE:
Repair procedures are under constant review, and therefore times are subject to change; those quoted here must be taken as guidance only. Always refer to DDW to obtain the latest repair time.
DDW requires the use of causal part numbers. Labor only claims must show the causal part number with a quantity of zero.
REPAIR PROCEDURE
CHECK COOLING SYSTEM FOR POTENTIAL OVERHEATING CAUSES
1. Check the coolant level.
CAUTION:
The expansion tank bleed screw has a torque limit of 4 Nm (35 lbf in). Care must be exercised not to damage the screw when tightening.
NOTE:
Global Technical Reference (GTR) lookup sequence is as follows:
GTR Home> NAS > Service Information/ LM - New Range Rover > Workshop Manuals> Bookmark "Powertrain/Engine/303-03A" LINK "Cooling System Draining, Filling and Bleeding (26.10.01)"
2. If the coolant level is low, perform the following:
^ Refer to GTR Section 303-3A (26.10.01) and pressure test the cooling system for leaks.
^ Top up as required.
3. Inspect the coolant pressure cap as follows: (Figure 1)
6 Verify that the correct coolant expansion tank cap with release pressure of 110 Kpa (16 psi) is installed.
6 Check the coolant expansion tank cap seal integrity.
^ Replace the cap if seal or pressure release is bad.
CAUTION:
A Midtronics PSC-550 Vehicle Power Supply must be connected to the vehicle battery during diagnosis.
4. Connect the Midtronics PSC-550 power supply to the vehicle battery.
5. Connect IDS to the vehicle and begin a new diagnostic session, by entering the correct VIN for the current vehicle.
6. Check the engine coolant sensor signal/function and repair as indicated.
7. Verify that the electro-viscous cooling fan assembly is operating correctly.
^ Check for wiring harness/electrical connection problems.
^ Ensure that the cooling fan is not making excessive contact with the fan cowl brushes, restricting the fan speed:
^ Check that the fan can achieve a minimum speed of 200 RPM Using IDS. (Select 'Engine Systems' - 'Datalogger' - Viscous Fan Speed Sensor).
NOTE:
Part PGF500340 has shorter brush filaments, allowing the fan to rotate at the correct speed.
8. If the fan does not meet the minimum speed, replace the upper right quadrant of the fan cowl part number PGF500340 as follows: (Figure 2)
^ Refer to GTR Range Rover (LM) Workshop Manual Section 414-00, and disconnect the battery ground cable.
^ Release the cooling fan wiring harness.
^ Refer to GTR Range Rover (LM) Workshop Manual Section 303-03, Cooling Fan (26.25.19) and remove the cooling fan.
^ Renew fan brush with new brush (PGF500340).
^ Install the cooling fan.
^ Secure the cooling fan wiring harness.
^ Connect the battery.
^ Retest the fan minimum speed using IDS.
9. If the vehicle is supercharged, perform the following:
^ Confirm that the electric water pump is functioning.
^ Refer to Technical Bulletin LTB00041 and check wiring harness, wiring connections and continuity before suspecting the pump assembly.
10. Check for correct coolant by monitoring the bottom radiator hose to the thermostat housing and confirming that temperature of the hose relates to the temperature gauge reading:
11. If the bottom hose does not feel warm/hot before the gauge indicates engine overheat, refer to GTR Range Rover Workshop Manual Section 303-3A, Thermostat (26.45.01) and replace the thermostat.
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