Diagnostic Procedure: Notes

Do you have CONSULT-II?

Yes or No

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

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  .

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  .

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) 

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

   Courtesy of NISSAN MOTOR CO., U.S.A.

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

   Courtesy of NISSAN MOTOR CO., U.S.A.

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
   Courtesy 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

Refer to COMPONENT INSPECTION  .

OK or NG

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

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

1. Inspection end