Cooling System: Testing and Inspection
ON VEHICLE INSPECTION1. CHECK COOLING SYSTEM FOR LEAKAGE
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. Fill the radiator with coolant, then attach a radiator cap tester.
c. Warm up the engine.
d. Pump it to 118 kPa (1.2 kgf/cm2, 17.1 psi), then check that the pressure does not drop.
If the pressure drops, check the hoses, radiator and water pump for leakage. If there are no signs of external coolant leaks, check the heater core, cylinder block and head.
e. Reinstall the radiator cap.
2. CHECK ENGINE COOLANT LEVEL OF RESERVOIR
a. The engine coolant should be between the LOW and FULL lines when the engine is cold.
If low, check for leakage 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
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 for any excessive deposits of rust or scale around the radiator cap and radiator filler hole; the coolant should be free of oil.
If excessively dirty, replace the coolant.
c. Reinstall the radiator cap.
4. CHECK FIN FOR BLOCKAGE
a. If the fins are clogged, wash them with water or a steam cleaner, then dry them with compressed air.
NOTICE:
- If the distance between the steam cleaner and core is too small, there is a possibility of damaging the fins, so keen to the following injection distances.
- 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 valve opening temperature is inscribed on the thermostat.
a. Immerse the thermostat in water, then 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 (0.39 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 fully 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 pressure valve with engine coolant or water.
- When performing the following steps (a) and (b), keep the tester at an angle of 30° or more above the horizontal.
a. Using a radiator cap tester, slowly pump and check that air is coming from the vacuum valve.
Pumping speed: 1 push every 3 seconds or more
NOTICE: Push the pump at a constant speed.
If air does not come from the vacuum valve, replace the radiator cap.
b. Pump the tester, then measure the relief valve opening pressure.
Pumping speed: 1 push within 1 second
NOTICE: The above pumping speed is for the first pumping only (in order to close the vacuum valve). After the first pumping, the pumping 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.