Diagnostic Procedure: Notes

WARNING: This page is about a different car, the 2005 Nissan Quest. However, it is still accessible from the selected car via links, so may be relevant.

INSPECTION START
Do you have CONSULT-II?

Yes or No
- Yes: GO TO 2.
- No: GO TO 3.
CHECK COOLING FAN OPERATION
With CONSULT-II
1. Start engine and let it idle.
2. Select "COOLING FAN" in "ACTIVE TEST" mode with CONSULT-II.
  
  Fig 1: CONSULT-II Active Test
  Courtesy of NISSAN MOTOR CO., U.S.A.
3. Make sure that cooling fans-1 and -2 operate at each speed (LOW/MID/HI).
OK or NG
- OK: GO TO 4.
- NG: Check cooling fan control circuit. (Go to "PROCEDURE A ".)
CHECK COOLING FAN OPERATION
Without CONSULT-II
1. Perform "IPDM E/R auto active test" and check cooling fan motors operation, refer to "AUTO ACTIVE TEST ".
2. Make sure that cooling fans-1 and -2 operate at each speed (Low/Middle/High).
OK or NG
- OK: GO TO 4.
- NG: Check cooling fan control circuit. (Go to "PROCEDURE A ".)
CHECK COOLING SYSTEM FOR LEAK
Apply pressure to the cooling system with a tester, and check if the pressure drops.

Fig 2: Applying Pressure To Cooling System With Tester
Courtesy of NISSAN MOTOR CO., U.S.A.
- 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
- OK: GO TO 5.
- NG: Check the following for leak. Refer to "CHECKING COOLING SYSTEM FOR LEAKS ".
  - Hose
  - Radiator
  - Water pump
CHECK RADIATOR CAP
Apply pressure to cap with a tester.

Fig 3: Applying Pressure To Cap
Courtesy of NISSAN MOTOR CO., U.S.A.
- Radiator cap relief 59-98 kPa (0.6 -1.0 kg/cm ²
- pressure: 9-14 psi)
OK or NG
- OK: GO TO 6.
- NG: Replace radiator cap.
CHECK THERMOSTAT
1. Check valve seating condition at normal room temperatures.
  It should seat tightly.
2. Check valve opening temperature and valve lift.
  
  Fig 4: Checking Valve Opening Temperature
  Courtesy of NISSAN MOTOR CO., U.S.A.
  - Valve opening temperature: 82°C (180°F) [standard]
  - Valve lift: More than 8.6 mm/95°C (0.339 in/203°F)
3. Check if valve is closed at 5°C (9°F) below valve opening temperature.
  For details, refer to "THERMOSTAT AND THERMOSTAT HOUSING ".
OK or NG
- OK: GO TO 7.
- NG: Replace thermostat
CHECK ENGINE COOLANT TEMPERATURE SENSOR
Refer to "COMPONENT INSPECTION ".

OK or NG
- OK: GO TO 8.
- NG: Replace engine coolant temperature sensor.
CHECK MAIN 12 CAUSES
If the cause cannot be isolated, go to "MAIN 12 CAUSES OF OVERHEATING ".
- : INSPECTION END