Diagnostic Procedure: Notes

WARNING: This page is about a different car, the 2006 Nissan Titan. 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 MOTOR OPERATION
With CONSULT-II
1. Start engine and let it idle.
2. Select "COOLING FAN" in "ACTIVE TEST" mode with CONSULT-II.
3. Make sure that cooling fan operates.
OK or NG

OK: GO TO 4.

NG: Check cooling fan control circuit. (Go to "PROCEDURE A ".)
CHECK COOLING FAN MOTOR OPERATION
Without CONSULT-II
1. Disconnect engine coolant temperature sensor harness connector.
2. Connect 150Ω resistor to engine coolant temperature sensor harness connector.
3. Start engine and let it idle.
4. Make sure that cooling fan operates.
OK or NG

OK: GO TO 4.

NG: Check cooling fan control circuit. (Go to "PROCEDURE A ".)

Fig 2: Connecting 150 Ohms Resistor To Engine Coolant Temperature Sensor Harness Connector
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)

Fig 3: Checking Cooling System For Leak
Courtesy of NISSAN MOTOR CO., U.S.A.

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
- Radiator cap
- Water pump
- Reservoir tank
CHECK RESERVOIR TANK CAP
Apply pressure to cap with a tester.

Reservoir tank cap relief pressure: 95 - 125 kPa (0.97 - 1.28 kg/cm ² , 14 - 18 psi)

OK or NG

OK: GO TO 6.

NG: Replace radiator cap.

Fig 4: 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: 82°C (180°F) [standard]
  
  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 PIPING ".
Fig 5: Checking Thermostat Valve Opening Temperature And Valve Lift
Courtesy of NISSAN MOTOR CO., U.S.A.

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