Diagnostic Procedure: Notes

INSPECTION START
Do you have CONSULT-II?

Yes or No
1. Yes: GO TO 2.
2. No: GO TO 4.
CHECK COOLING FAN LOW SPEED OPERATION
With CONSULT-II
1. Start engine and let it idle.
2. Select "COOLING FAN" in "ACTIVE TEST MODE " with CONSULT-II and touch "LOW" on the CONSULT-II screen.
3. Make sure that cooling fans-1 and -2 operate at low speed.
OK or NG
1. OK: GO TO 3.
2. NG: Check cooling fan low speed control circuit. (Go to "PROCEDURE A ".)
  
  Fig 1: Consult-II Active Test Display
  Courtesy of NISSAN MOTOR CO., U.S.A.
CHECK COOLING FAN HIGH SPEED OPERATION
With CONSULT-II
1. Touch "HIGH" on the CONSULT-II screen.
2. Make sure that cooling fans-1 and -2 operate at higher speed than low speed.
OK or NG
1. OK: GO TO 6.
2. NG: Check cooling fan high speed control circuit. (Go to "PROCEDURE B ".)
  
  Fig 2: Consult-II Active Test Display
  Courtesy of NISSAN MOTOR CO., U.S.A.
CHECK COOLING FAN LOW SPEED OPERATION
Without CONSULT-II
1. Start engine and let it idle.
2. Turn air conditioner switch ON.
3. Turn blower fan switch ON.
4. Make sure that cooling fans-1 and -2 operate at low speed.
OK or NG
1. OK: GO TO 5.
2. NG: Check cooling fan low speed control circuit. (Go to "PROCEDURE A ".)
  
  Fig 3: Checking Cooling Fan Low Speed Operation
  Courtesy of NISSAN MOTOR CO., U.S.A.
CHECK COOLING FAN HIGH SPEED OPERATION
Without CONSULT-II
1. Turn ignition switch OFF.
2. Turn air conditioner switch and blower fan switch OFF.
3. Disconnect engine coolant temperature sensor harness connector.
4. Connect 150? resistor to engine coolant temperature sensor harness connector.
5. Restart engine and make sure that cooling fans-1 and -2 operate at higher speed than low speed.
OK or NG
1. OK: GO TO 6.
2. NG: Check cooling fan high speed control circuit. (Go to "PROCEDURE B ".)
  
  Fig 4: Checking Cooling Fan High Speed Operation
  Courtesy of NISSAN MOTOR CO., U.S.A.
CHECK COOLING SYSTEM FOR LEAK
Apply pressure to the cooling system with a tester, and check if the pressure drops.

Testing pressure: 157 kPa (1.6 kg/cm ² , 23 psi)

CAUTION: Higher than the specified pressure may cause radiator damage. Pressure should not drop.

OK or NG
1. OK: GO TO 7.
2. NG: Check the following for leaks.
  - Hose
  - Radiator
  - Water pump
    
    Fig 5: Applying Pressure To Cooling System With Tester
    Courtesy of NISSAN MOTOR CO., U.S.A.
CHECK RADIATOR CAP
Apply pressure to cap with a tester.

Radiator cap relief pressure: 59 - 98 kPa (0.6 - 1.0 kg/cm ² , 9 - 14 psi)

OK or NG
1. OK: GO TO 8.
2. NG: Replace radiator cap.
  
  Fig 6: Applying Pressure To Cap With Tester
  Courtesy of NISSAN MOTOR CO., U.S.A.
CHECK THERMOSTAT
1. Check valve seating condition at normal room temperatures.
  It should seat tightly.
2. Check valve opening temperature and valve lift.
  Valve opening temperature: 76.5°C (170°F) [standard]
  
  Valve lift: More than 8.6 mm/90°C (0.339 in/194°F)
3. Check if valve is closed at 5°C (9°F) below valve opening temperature.
OK or NG
1. OK: GO TO 9.
2. NG: Replace thermostat
  
  Fig 7: Checking Thermostat
  Courtesy of NISSAN MOTOR CO., U.S.A.
CHECK ENGINE COOLANT TEMPERATURE SENSOR
Refer to "COMPONENT INSPECTION ".

OK or NG
1. OK: GO TO 10.
2. NG: Replace engine coolant temperature sensor.
CHECK MAIN 12 CAUSES
If the cause cannot be isolated, go to "MAIN 12 CAUSES OF OVERHEATING ".
1. : INSPECTION END