Engine Cooling System: Diagnosis Toyota Sequoia I рестайлинг

INSPECTION

HINT

Check the coolant level when the engine is cold.

1. CHECK ENGINE COOLANT LEVEL AT RADIATOR RESERVOIR The engine coolant level should be between the "LOW" and "FULL" lines at normal temperature (20° C (68° F)). If low, check for leaks and add "Toyota Super Long Life Coolant" or similar high quality ethylene glycol based non-silicate, non-amine, non-nitrite, and non-borate coolant with long-life hybrid organic acid technology up to the "FULL" line.
2. CHECK ENGINE COOLANT QUALITY Remove the radiator cap. CAUTION: To avoid the danger of being burned, do not remove the radiator cap while the engine and radiator are still hot, as fluid and steam can be blown out under pressure. There should not be any excessive deposits of rust or scale around the radiator cap or radiator filler hole, and the coolant should be free from oil. If excessively dirty, clean the coolant passages and replace the coolant. Reinstall the radiator cap.

INSPECT THERMOSTAT

HINT

The thermostat is numbered with the valve opening temperature.

Scheme 1

Scheme 2

1. Immerse the thermostat in water and gradually heat the water.
2. Check the valve opening temperature. Valve opening temperature: 80 to 84° C (176 to 183° F) If the valve opening temperature is not as specified, replace the thermostat.
3. Check the valve lift. Valve lift: 10 mm (0.39 in.) or more at 95° C (203° F) If the valve lift is not as specified, replace the thermostat.
4. Check that the valve is fully closed when the thermostat is at low temperatures (below 40° C (104° F)).

If not closed, replace the thermostat.

Scheme 3

Scheme 4

1. PLACE THERMOSTAT IN WATER INLET HOUSING Install a new gasket to the thermostat. Insert the thermostat into the water inlet housing with the jiggle valve facing straight upward. HINT: The jiggle valve may be set within 30° of either side of the prescribed position.
2. INSTALL WATER INLET Install the water inlet with the 3 nuts. Torque: 19 N.m (195 kgf.cm, 14 ft.lbf)
3. FILL WITH ENGINE COOLANT
4. START ENGINE AND CHECK FOR COOLANT LEAKS
5. RECHECK ENGINE COOLANT LEVEL

Scheme 5

If fins are clogged, wash them with water or a steam cleaner and dry with compressed air.

Note. If the distance between the steam cleaner and the core is too close, there is a possibility of damaging the fin, so keep the following injection distance. PRESSURE INJECTION DISTANCE SPECIFICATION Injection Pressure Injection Distance 2,942 to 4,903 kpa (30 to 50 kg/cm 2 , 427 to 711 psi) 300 mm (11.811 in) 4,903 to 7,845 kpa (50 to 80 kg/cm 2 , 711 to 1,138 psi) 500 mm (19.685 in) If the fins are bent, straighten them with a screwdriver or pliers. Never apply water directly onto the electronic components.

Scheme 6

Scheme 7

1. REMOVE RADIATOR CAP CAUTION: To avoid the danger of being burned, do not remove the radiator cap while the engine and radiator are still hot, as fluid and steam can be blown out under pressure.
2. INSPECT RADIATOR CAP NOTE: If the radiator cap has contaminations, always rinse it with water. Before using a radiator cap tester, wet the relief valve and pressure valve with engine coolant or water. When performing steps (a) and (b) below, keep the tester at an angle of over 30° above the horizontal. Using a radiator cap tester, slowly pump the tester and check that air is coming from the vacuum valve. Pump speed: 1 push/(3 seconds or more) NOTE: Push the pump at a constant speed. If air is not coming from the vacuum valve, replace the radiator cap. Pump the radiator cap tester, and measure the relief valve opening pressure. Pump speed: 1 push within 1 second NOTE: This pump speed is for the first pump only (in order to close the vacuum valve). After this, the pump speed can be reduced. Opening pressure: OPENING PRESSURE SPECIFICATION Standard 74 to 103 kPa (0.75 to 1.05 kgf/cm 2 , 10.7 to 14.9 psi) Minimum 59 kPa (0.6 kgf/cm 2 , 8.6 psi) HINT: Use the tester's maximum reading as the opening pressure. If the opening pressure is less than minimum, replace the radiator cap.
3. INSPECT COOLING SYSTEM FOR LEAKS Fill the radiator with coolant and attach a radiator cap tester. Warm up the engine. Pump it to 118 kPa (1.2 kgf/cm 2 , 17.1 psi), and check that the pressure does not drop. If the pressure drops, check the hoses, radiator or water pump for leaks. If no external leaks are found, check the heater core, cylinder block and head.
4. REINSTALL RADIATOR CAP

Scheme 8

Scheme 9

1. REMOVE ENGINE UNDER COVER
2. DRAIN ENGINE COOLANT
3. DISCONNECT RADIATOR RESERVOIR HOSE FROM RADIATOR
4. DISCONNECT UPPER RADIATOR HOSE FROM RADIATOR
5. DISCONNECT LOWER RADIATOR HOSE FROM RADIATOR
6. DISCONNECT A/T OIL COOLER HOSES FROM RADIATOR
7. REMOVE NO. 2 FAN SHROUD Remove the 2 clips and No.2 fan shroud.
8. REMOVE RADIATOR ASSEMBLY Remove the 4 bolts and radiator assembly.
9. REMOVE NO. 1 FAN SHROUD Remove the 4 bolts and No.1 fan shroud.

Scheme 10

1. INSTALL NO. 1 FAN SHROUD Install the No.1 fan shroud with the 4 bolts. Torque: 5.0 N.m (50 kgf.cm, 44 in.lbf)
2. INSTALL RADIATOR ASSEMBLY Set the radiator bracket hooks to the radiator support holes. Install the 4 bolts. Torque: 12 N.m (120 N.m, 9 ft.lbf)
3. INSTALL NO. 2 FAN SHROUD Install the No.2 fan shroud with the 2 clips.
4. CONNECT A/T OIL COOLER HOSES TO RADIATOR
5. CONNECT UPPER RADIATOR HOSE TO RADIATOR
6. CONNECT LOWER RADIATOR HOSE TO RADIATOR
7. CONNECT RADIATOR RESERVOIR HOSE TO RADIATOR
8. FILL WITH ENGINE COOLANT
9. START ENGINE AND CHECK FOR ENGINE COOLANT LEAKS
10. RECHECK ENGINE COOLANT LEVEL
11. INSTALL ENGINE UNDER COVER