Diagnostic Procedure

Start engine and make sure that cooling fan (crankshaft driven) operates.

OK or NG 

1. OK: GO TO 2.
2. NG: Check cooling fan (crankshaft driven). Refer to "COOLING FAN (CRANKSHAFT DRIVEN) ".

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

Fig 1: Checking Cooling System For Leakage Using Tester

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

Pressure should not drop. 

OK or NG 

1. OK: GO TO 3.
2. NG: Check the following for leak 

• Hose
• Radiator
• Water pump

  Refer to "WATER PUMP " .

Apply pressure to cap with a tester and check radiator cap relief pressure.

Fig 2: Checking Radiator Cap Using Tester

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

Radiator cap relief pressure: 

59 - 98 kPa  (0.6 - 1.0 kg/cm² , 9 - 14 psi)

OK or NG 

1. OK: GO TO 4.
2. NG: Replace radiator cap.

1. Check valve seating condition at normal room temperatures.

   It should seat tightly. 

2. Check valve opening temperature and valve lift.
   Fig 3: Checking Valve Opening Temperature And Valve Lift

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

   Valve opening temperature: 

   76.5°C (170°F) [standard] 

   Valve lift: 

   More than 8 mm/108°C (0.315 in/226°F) 

3. Check if valve is closed at 5°C (9°F) below valve opening temperature.

   For details, refer to "THERMOSTAT " .

OK or NG 

1. OK: GO TO 5.
2. NG: Replace thermostat

Check resistance as shown in the figure.

Fig 4: Checking Engine Coolant Temperature Sensor Resistance

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

< Reference data> 

Fig 5: Temperature/Resistance Specification Chart

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

Fig 6: Temperature/Resistance Graph

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

OK or NG 

1. OK: GO TO 6.
2. NG: Replace engine coolant temperature sensor.

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

1. INSPECTION END