Cooling System On-Vehicle Inspection

Fill the radiator with coolant and attach a radiator cap tester to the radiator reservoir.

Warm up the engine.

Using the radiator cap tester, increase the pressure inside the radiator to 123 kPa (1.3 kgf/cm², 17.8 psi), and check that the pressure does not drop.
If the pressure drops, check the hoses, radiator and water pump for leaks.
If no external leaks are found, check the cylinder block and cylinder head.

Check that the engine coolant level is between the LOW and FULL lines when the engine is cold.
If the engine coolant is low, check for leaks and add "TOYOTA Super Long Life Coolant (SLLC)" or similar high quality ethylene glycol based non-silicate, non-amine, non-nitrite and non-borate coolant with long-life hybrid organic acid technology to the FULL line.

NOTICE:

Do not substitute plain water for engine coolant.

Remove the radiator reservoir cap.

CAUTION:

Do not remove the radiator reservoir cap while the engine and radiator are still hot. Pressurized, hot engine coolant and steam may be released and cause serious burns.

Check if there are excessive deposits of rust or scales around the radiator reservoir cap and radiator filler hole. Also, the coolant should be free of oil.
If excessively dirty, replace the coolant.

Install the radiator reservoir cap.

Check that the fluid coupling is not damaged and that no silicon oil leaks.
If necessary, replace the fluid coupling assembly.