Engine Cooling System: Overview Toyota 4Runner IV

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1. INSPECT COOLING SYSTEM FOR LEAKS 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. Fill the radiator with coolant, then attach a radiator cap tester. Warm up the engine. Pump it to 118 kPa (1.2kgf/cm 2 ,17.1 psi), then check that the pressure does not drop. HINT If the pressure drops, check the hoses, radiator and water pump for leaks. If no external leaks are found, check the heater core, cylinder block and cylinder head.
2. CHECK ENGINE COOLANT LEVEL AT RESERVOIR The engine coolant level should be between the "LOW" and "FULL" lines. 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.
3. 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. Check the radiator cap and radiator filler hole for rust and dirt. The coolant should be free from oil. HINT If the coolant is excessively dirty, replace the coolant. Reinstall the radiator cap.
4. INSPECT FIN BLOCKAGE If the fins are clogged, wash them with water or a steam cleaner. After cleaning, dry the fins with compressed air. NOTE: If the distance between the steam cleaner and core is too close, there is a possibility of damaging the fins, so keep the following injection distance. INJECTION PRESSURE - INJECTION DISTANCE SPECIFICATION Injection Pressure kPa (kg/cm 2 , psi) Injection Distance mm (in.) 2,942 to 4,903 (30 to 50, 427 to 711) 300 (11.811) 4,903 to 7,845 (50 to 80, 711 to 1,138) 500(19.685) If the fins are bent, straighten them with a screwdriver or plier. Never apply water directly to the electronic components.

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1. INSPECT WATER PUMP ASSY Visually check the air hole and water hole for coolant leakage. If leakage is found, replace the water pump. Turn the pulley, then check that the water pump bearing moves smoothly and quietly. If necessary, replace the water pump.
2. INSPECT FLUID COUPLING ASSY Check the fluid coupling for damage or silicon oil leaks. If necessary, replace the fluid coupling.
3. INSPECT WATER INLET W/THERMOSTAT HINT The valve opening temperature is inscribed on the thermostat. Immerse the thermostat in the water, then heat the water gradually. Check the valve opening temperature of the thermostat. Valve opening temperature: 80 to 84°C (176 to 183°F) If the valve opening temperature is not as specified, replace the thermostat. Check the valve lift. Valve lift: 8 mm (0.31 in.) or more at 95°C (203°F) If the valve lift is not as specified, replace the thermostat. Check that the valve is fully closed when the thermostat is at low temperature (below 40°C (104°F)). If not fully closed, replace the thermostat.
4. INSPECT RADIATOR CAP SUB-ASSY NOTE: If the radiator cap is contaminated, rinse it with water. Before using a radiator cap tester, wet the relief valve and pressure valve with engine coolant or water. Using a radiator cap tester, slowly pump the tester and check that air is coming from the vacuum valve. Pumping speed: 1 push per 3 seconds or longer NOTE: Push the pump at a constant speed. HINT If air is not coming from the vacuum valve, replace the reservoir cap. Pump the tester, then measure the relief valve opening pressure. Standard opening pressure: 93 to 123 kPa (0.95 to 1.25 kgf/cm 2 ,13.5 to 17.8 psi) Minimum opening pressure: 78 kPa (0.8 kgf/cm 2 ,11.4 psi) NOTE: The following pumping speed is for the first time (in order to close the vacuum valve). After the first pumping, the pumping speed can be reduced. HINT: Pumping speed: 1 push within 1 second The tester's maximum reading is the opening pressure value. If the opening pressure is less than minimum, replace the radiator cap.

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1. DRAIN ENGINE COOLANT 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. Remove the service hole cover from the engine under cover. Install a vinyl hose to the drain on the radiator side. Fix the vinyl hose with tape. Loosen the 3 drain plugs on the engine and radiator, then drain the coolant. Remove the radiator cap. Drain the coolant from the reservoir tank. Put in the 3 drain plugs. Torque: 13 N.m (130 kgf.cm, 9 ft.lbf) for the engine Remove the vinyl hose from the radiator.
2. ADD ENGINE COOLANT Slowly fill the system with engine coolant. Capacity: 9.8 liters (10.4 US qts, 8.6 Imp. qts) HINT: Use of improper coolants may damage the engine cooling system. Use "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. New Toyota vehicles are filled with Toyota Super Long Life Coolant (color is pink, premixed ethylene-glycol concentration is approximately 50% and freezing temperature is -35°C (-31°F)). When replacing the coolant, Toyota Super Long Life Coolant is recommended. Observe the coolant level inside the radiator by pressing the inlet and outlet radiator hoses several times by hand. If the coolant level goes down, add the coolant. NOTE: Do not use plain water alone. Install the radiator cap. Bleed the cooling system. Start the engine, then open the heater water valve. Maintain the engine speed at 2,000 to 2,500 rpm to warm up the engine. Stop the engine, then wait until the engine coolant cools down. Add coolant into the reservoir until the coolant level is "FULL".
3. CHECK FOR ENGINE COOLANT LEAKS Fill the radiator with coolant, then attach a radiator cap taster. Pump it to 118 kPa (1.2 kgf/cm 2 17.1 psi), then check for leakage.

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1. REMOVE ENGINE UNDER COVER SUB-ASSY NO. 1 Remove the 4 bolts and engine under cover.
2. DRAIN ENGINE COOLANT (See «COOLANT (1GR-FE)»(ref-235178-S08120220652006061400000) )
3. REMOVE RADIATOR SUPPORT SEAL UPPER Remove the 11 clips and radiator support seal upper.
4. LOOSEN FAN W/ FLUID COUPLING Loosen the 4 fluid coupling bolts.
5. REMOVE FAN AND GENERATOR V BELT (See «FAN AND GENERATOR V BELT»(ref-235151-S00974816002006061400000) )
6. REMOVE FAN W/ FLUID COUPLING Unfasten the hose clamp, and then separate the 2 oil cooler hoses from the fan shroud. Disconnect the radiator reserve tank hose. Remove the 2 fan shroud bolts and radiator reserve tank bolt. Remove the 4 fluid coupling nuts, and then remove the fan w/ fluid coupling and fan shroud together. Remove the fan pulley.
7. DISCONNECT VENTILATION HOSE NO. 2
8. REMOVE AIR CLEANER ASSY
9. REMOVE WATER INLET Disconnect the 2 oil cooler hoses (w/ oil cooler). Disconnect the 2 radiator hoses. Disconnect the 5 water by-pass hoses. Remove the 5 bolts and water inlet. Remove the O-ring from the water outlet pipe. Remove the gasket from the water pump.
10. REMOVE IDLER PULLEY SUB-ASSY NO. 2 Remove the 2 bolts and 2 idler pulleys.
11. REMOVE GENERATOR ASSY (See «GENERATOR»(ref-163567-S22705679482004070600000) )
12. SEPARATE COOLER COMPRESSOR ASSY (See «CRANKSHAFT POSITION SENSOR»(ref-151984-S30853055372003010900000) )
13. REMOVE V-RIBBED BELT TENSIONER ASSY (See «REPLACEMENT»(ref-235151-S06007633702006061400000) )
14. REMOVE WATER PUMP ASSY Remove the 17 bolts, water pump and gasket.
15. INSTALL WATER PUMP ASSY Install a new gasket and the water pump with the 17 bolts. Torque: 9.0 N.m (92 kgf.cm, 80 in.lbf) for 10 mm (0.39 in.) head 23 N.m (235 kgf.cm, 17 ft.lbf) for 12 mm (0.47 in.) head
16. INSTALL V-RIBBED BELT TENSIONER ASSY (See «REPLACEMENT»(ref-235151-S06007633702006061400000) )
17. INSTALL COOLER COMPRESSOR ASSY (See «CRANKSHAFT POSITION SENSOR»(ref-151984-S30853055372003010900000) )
18. INSTALL GENERATOR ASSY (See «GENERATOR»(ref-163567-S22705679482004070600000) )
19. INSTALL IDLER PULLEY SUB-ASSY NO. 2 Install the 2 idler pulleys with the 2 bolts. Torque: 39 N.m (398 kgf.cm, 29 ft.lbf)
20. INSTALL WATER INLET Install a new O-ring to the water outlet pipe. Install a new gasket to the water pump. Apply soapy water to the O-ring. Install the water inlet with the 5 bolts. Torque: 9.0 N.m (92 kgf.cm, 80 in.lbf) Connect the 5 water by-pass hoses. Connect the 2 radiator hoses. Connect the 2 oil cooler hoses (w/ oil cooler).
21. INSTALL AIR CLEANER ASSY
22. CONNECT VENTILATION HOSE NO. 2
23. INSTALL FAN W/ FLUID COUPLING Put the fan pulley to the water pump. Put the fan w/ fluid coupling and fan shroud together. Temporarily install the 4 fluid coupling nuts. Tighten the 2 fan shroud bolts and radiator reserve tank bolt. Torque: 5.0 N.m (51 kgf.cm, 44 in.lbf) Connect the reserve tank hose. Fasten the 2 oil cooler hoses with the hose clamp.
24. INSTALL FAN AND GENERATOR V BELT (See «FAN AND GENERATOR V BELT»(ref-235151-S00974816002006061400000) )
25. FULLY TIGHTEN FAN W/ FLUID COUPLING Tighten the 4 fluid coupling bolts. Torque: 21 N.m (214 kgf.cm, 15 ft.lbf)
26. INSTALL RADIATOR SUPPORT SEAL UPPER
27. ADD ENGINE COOLANT (See «COOLANT (1GR-FE)»(ref-235178-S08120220652006061400000) )
28. CHECK FOR ENGINE COOLANT LEAKS (See «COOLING SYSTEM (1GR-FE)»(ref-235178-S21249499762006061400000) )
29. INSTALL V-BANK COVER Install the V-bank cover with the 2 nuts. Torque: 7.5 N.m (76 kgf.cm, 66 in.lbf)
30. INSTALL ENGINE UNDER COVER SUB-ASSY NO. 1 Install the engine under cover with the 4 bolts. Torque: 29 N.m (296 kgf.cm, 21 ft.lbf)