Engine Cooling System (Service Information) (Base): Overview Toyota Prius Plug-in

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1. REMOVE NO. 1 ENGINE UNDER COVER
2. DRAIN COOLANT (for Engine) NOTE: Do not remove the reservoir tank cap and radiator drain cock plug while the engine and radiator are still hot. Pressurized, hot engine coolant and steam may be released and cause serious burns. Loosen the radiator drain cock plug and drain the coolant. TEXT IN ILLUSTRATION *1 Reservoir Tank Cap *2 Radiator Drain Cock Plug HINT: Collect the coolant in a container and dispose of it according to the local regulations.
3. ADD COOLANT (for Engine) Tighten the radiator drain cock plug. Remove the reservoir tank cap. Add coolant to B line of the reservoir tank. TEXT IN ILLUSTRATION *1 B Line Standard Capacity Item Capacity Engine coolant w/ Exhaust Heat Recirculation System: 7.2 liters (7.6 US qts, 6.3 lmp. qts) w/o Exhaust Heat Recirculation System: 6.5 liters (6.8 US qts, 5.7 lmp. qts) HINT: TOYOTA vehicles are filled with TOYOTA SLLC at the factory. In order to avoid damage to the engine cooling system and other technical problems, only use TOYOTA SLLC or similar high quality ethylene glycol based non-silicate, non-amine, non-nitrite, non-borate coolant with long-life hybrid organic acid technology (coolant with long-life hybrid organic acid technology is a combination of low phosphates and organic acids). NOTE: Never use water as a substitute for engine coolant. Squeeze the inlet and outlet radiator hoses several times by hand, and then check the level of the coolant. If the coolant level is low, add coolant. Install the reservoir tank cap. Put the engine in inspection mode. Refer to «INSPECTION MODE PROCEDURE»(ref-551389-S33941292062013051500000). Bleed air from the cooling system. NOTE: Before starting the engine, turn the A/C switch off. Adjust the heater control to the maximum hot setting. Adjust the blower speed to low setting. Warm up the engine until the thermostat opens. While the thermostat is open, allow the coolant to circulate for several minutes. HINT: The thermostat opening timing can be confirmed by squeezing the inlet radiator hose by hand, and sensing vibrations when the engine coolant starts to flow inside the hose. WARNING: When squeezing the radiator hose: Wear protective gloves. Be careful as the radiator hoses are hot. Keep your hands away from the radiator fan. Squeeze the inlet and outlet radiator hoses several times by hand to bleed air from the system. WARNING: When squeezing the radiator hose: Wear protective gloves. Be careful as the radiator hoses are hot. Keep your hands away from the radiator fan. After the engine has cooled down, check that the coolant level is between full and low. TEXT IN ILLUSTRATION *1 Full Line *2 Low Line If the coolant level is low, add coolant to the full line on the reservoir tank.
4. INSPECT FOR COOLANT LEAK (for Engine) . Refer to «ON-VEHICLE INSPECTION - Step 1»(/toyota/prius-plug-in/2012-2014/remont/cooling-fan/#engine-cooling-system-inspection-base)
5. INSTALL NO. 1 ENGINE UNDER COVER

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1. REMOVE NO. 1 ENGINE UNDER COVER
2. REMOVE INLET AIR CLEANER ASSEMBLY . Refer to «REMOVAL - Step 31»(/toyota/prius-plug-in/2012-2014/remont/mechanical/#engine-mechanical-service-information-base)
3. DRAIN COOLANT (for Engine) See step 2
4. REMOVE ENGINE WATER PUMP ASSEMBLY Disconnect the connector from the engine water pump assembly. Remove the 5 bolts and engine water pump assembly from the timing chain cover. Remove the gasket from the engine water pump assembly.

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1. INSTALL ENGINE WATER PUMP ASSEMBLY Install a new gasket. HINT: Be sure to clean the contact surfaces. Install the engine water pump assembly to the timing chain cover with the 5 bolts. Bolt A Torque: 26 N*m (260 kgf*cm, 19 ft.*lbf) Bolt B Torque: 21 N*m (214 kgf*cm, 15 ft.*lbf) Bolt Length Item Length Bolt A 35 mm (1.38 in.) Bolt B 18 mm (0.709 in.) Connect the connector to the engine water pump assembly.
2. ADD COOLANT (for Engine) See step 3
3. INSPECT FOR COOLANT LEAK (for Engine) . Refer to «ON-VEHICLE INSPECTION - Step 1»(/toyota/prius-plug-in/2012-2014/remont/cooling-fan/#engine-cooling-system-inspection-base)
4. INSTALL INLET AIR CLEANER ASSEMBLY . Refer to «INSTALLATION - Step 68»(/toyota/prius-plug-in/2012-2014/remont/mechanical/#engine-mechanical-service-information-base)
5. INSTALL NO. 1 ENGINE UNDER COVER

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1. REMOVE NO. 1 ENGINE UNDER COVER
2. DRAIN ENGINE COOLANT (for Engine) See step 2
3. REMOVE ENGINE COOLANT TEMPERATURE SENSOR Disconnect the engine coolant temperature sensor connector. Using a union nut wrench (19 mm), remove the engine coolant temperature sensor. NOTE: Do not apply any excessive force to the heater pipe when removing the engine coolant temperature sensor.

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1. INSPECT ENGINE COOLANT TEMPERATURE SENSOR Measure the resistance according to the value(s) in the table below. Standard Resistance Condition Specified Condition Approximately 20°C (68°F) 2.32 to 2.59 kohms Approximately 80°C (176°F) 0.310 to 0.326 kohms NOTE: When checking the engine coolant temperature sensor in water, keep the terminals dry. After the check, dry the engine coolant temperature sensor. If the resistance is not as specified, replace the engine coolant temperature sensor.

See also:
• ON-VEHICLE INSPECTION - Step 1
• REMOVAL - Step 31
• REMOVAL - Step 1
• REMOVAL - Step 9
• INSTALLATION - Step 2