Cooling System: Testing and Inspection
COOLING SYSTEM
ON-VEHICLE INSPECTION
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. Thermal expansion will cause hot engine coolant and steam to blow out from the radiator.
a. Fill the radiator with coolant and attach a radiator cap tester.
b. Warm up the engine.
c. Pump it to 118 kPa (1.2 kgf/cm2, 17.1 psi), and check that the pressure does not drop.
If the pressure drops, check the hoses, radiator and water pump for leaks. If there are no signs or traces of external coolant
2. CHECK ENGINE COOLANT LEVEL AT RESERVOIR
a. The engine coolant should be between the "LOW" and "FULL" lines, when the engine is cold.
If low, check for leaks and add "Toyota Long Life Coolant" or equivalent up to the "FULL" line.
Coolant type
"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.
Mix 50/50 with distilled water. Do not use plain water alone.
NOTE: "Toyota Super Long Life Coolant" is filled in your Lexus vehicle at factory fill. In order to avoid technical problems, only 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. Follow the manufacturer dilution recommendations on the label.
1. Do not use alcohol type antifreeze or plain water alone.
2. DO NOT FURTHER DILUTE PRE-MIXED MANUFACTURER APPROVED ETHYLENE GLYCOL BASED COOLANT IF USED.
3. CHECK ENGINE COOLANT QUALITY
a. 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. Thermal expansion will cause hot engine coolant and steam to blow out from the radiator.
b. Check if there is any excessive deposits of rust or scale around the radiator cap and radiator filler hole; the coolant should free of oil.
HINT: If excessively dirty, replace the coolant.
c. Reinstall the radiator cap.
4. INSPECT FINS BLOCKAGE
a. If fins are clogged, wash them with water or a steam cleaner and dry with compressed air.
NOTICE:
^ If the distance between the steam cleaner and the core is too close, there is a possibility of damaging the fins, so keep the following injection distance.
^ If the fins are bent, straighten them with a screwdriver or pliers.
^ Be careful not to expose electronic components to water.
INSPECTION
1. INSPECT THERMOSTAT
HINT: The thermostat is numbered with the valve opening temperature.
a. Immerse the thermostat in water and gradually heat the water.
b. 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.
c. Check the valve lift.
Valve lift: 10 mm (0.394 inch) or more at 95°C (203°F)
If the valve lift is not as specified, replace the thermostat.
d. Check that the valve is fully closed when the thermostat is at low temperatures (below 77°C (171°F)).
If not closed, replace the thermostat.
2. INSPECT RADIATOR CAP SUB-ASSEMBLY
NOTICE:
^ If the radiator cap is contaminated, rinse it with water.
^ Before using a radiator cap tester, wet the relief valve and the pressure valve with engine coolant or water.
^ When performing following steps (a) and (b), keep the tester at an angle of over 30° above horizontal.
a. 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
NOTICE: Push the pump at a constant speed.
If air is not coming from the vacuum valve, replace the radiator cap.
b. Pump the tester and measure the relief valve opening pressure.
Pump speed: 1 push within 1 second
NOTICE: The above pump speed is for the first pump only (in order to close the vacuum valve). After the first pump, the pump speed can be reduced.
Standard opening pressure: 74 to 103 kPa (0.75 to 1.05 kgf/cm2, 10.7 to 14.9 psi)
Minimum opening pressure: 59 kPa (0.6 kgf/cm2, 8.6 psi)
If the opening pressure is less than minimum, replace the radiator cap.
HINT: Use the tester's maximum reading as the opening pressure.
3. INSPECT WATER PUMP ASSEMBLY
a. Visually check the drain hole for coolant leakage.
If leakage is found, replace the water pump.
b. Turn the pulley, and check that the water pump bearing moves smoothly and does not make noise.
If necessary, replace the water pump.