2004 Infiniti FX45FACTORY OEM SERVICE PROCEDURE

Diagnostic Procedure: Notes

  1. Inspection Start 

    Do you have CONSULT-II?

    Yes or No

    1. Yes: go to 2.
    2. No: go to 3.

  2. Check Cooling Fan Motor Operation 

    With CONSULT-II 

    1. Start engine and let it idle.
    2. Select COOLING FAN in ACTIVE TEST mode with CONSULT-II. See Figure .
    3. Make sure that cooling fan operate.

    OK or NG

    1. OK: go to 4.
    2. NG: Check cooling fan control circuit. Go to PROCEDURE A  .

  3. Check Cooling Fan Motor Operation 

    Without CONSULT-II 

    1. Disconnect engine COOLANT temperature sensor harness connector.
    2. Connect 150ohm resistor to engine COOLANT temperature sensor harness connector.
    3. Start engine and let it idle.
    4. Make sure that cooling fan operate.

    OK or NG

    1. OK: go to 4.
    2. NG: Check cooling fan control circuit. Go to PROCEDURE A  .

  4. Check Cooling System For Leak 

    Apply pressure to the cooling system with a tester, and check if the pressure drops.

    1. Testing pressure: 157 kPa (1.6 kg/cm2  , 23 psi) 
    CAUTION: Higher than the specified pressure may cause radiator damage. Pressure should not drop.

    OK or NG

    1. OK: go to 5.
    2. NG: Check the following for leak. Refer to LEAK CHECK .
      • Hose
      • Radiator
      • Water pump
      Fig 1: Pressure Testing Cooling System
      G00345276Courtesy of NISSAN MOTOR CO., U.S.A.

  5. Check Radiator Cap 

    Apply pressure to cap with a tester.

    1. Radiator cap relief pressure: 59 - 98 kPa (0.6 - 1.0 kg/cm2  , 9 - 14 psi) 

    OK or NG

    1. OK: go to 6.
    2. NG: Replace radiator cap.
      Fig 2: Pressure Testing Radiator Cap
      G00345277Courtesy of NISSAN MOTOR CO., U.S.A.

  6. Check Thermostat 
    1. Check valve seating condition at normal room temperatures.

      It should seat tightly  .

    2. Check valve opening temperature and valve lift.
        Fig 3: Testing Thermostat Valve
        G00345278Courtesy of NISSAN MOTOR CO., U.S.A.
      1. Valve opening temperature: 82° C (180° F) [standard] 
      2. Valve lift: More than 10.0 mm/95° C (0.394 in/203° F) 
    3. Check if valve is closed at 5° C (9° F) below valve opening temperature.

      For details, refer to THERMOSTAT AND WATER CONTROL VALVE .

    OK or NG

    1. OK: go to 7.
    2. NG: Replace thermostat

  7. Check Engine COOLANT Temperature Sensor 

    Refer to COMPONENT INSPECTION  .

    OK or NG

    1. OK: go to 8.
    2. NG: Replace engine COOLANT temperature sensor.

  8. Check Main 12 Causes 

    If the cause cannot be isolated, go to MAIN 12 CAUSES OF OVERHEATING  .

    1. Inspection end 
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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