Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Cooling System

On-vehicle Inspection

ON-VEHICLE INSPECTION

CAUTION / NOTICE / HINT

CAUTION:

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

PROCEDURE

1. INSPECT FOR COOLANT LEAK

CAUTION:

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

(a) Remove the radiator cap sub-assembly.

(b) Fill the radiator assembly with engine coolant, and then install a radiator cap tester.

*a Radiator Cap Tester

(c) Warm up the engine.

(d) Pump the radiator cap tester to 123 kPa (1.3 kgf/cm2, 18 psi), and then check that the pressure does not drop.

(e) Remove the radiator cap tester.

(f) Install the radiator cap sub-assembly.

2. INSPECT ENGINE COOLANT LEVEL IN RESERVOIR TANK

(a) Check that the engine coolant level is between the LOW line and FULL line when the engine is cold. If the engine coolant level is low, check for leaks and add engine coolant to the FULL line. NOTICE: Do not substitute plain water for engine coolant.

*a FULL Line *b LOW Line

3. INSPECT ENGINE COOLANT QUALITY

CAUTION:

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

(a) Remove the radiator cap sub-assembly.

(b) Check if there are any excessive deposits of rust or scale around the radiator cap sub-assembly and water filler hole. Also, the engine coolant should be free of oil.

If excessively dirty, replace the engine coolant.

(c) Install the radiator cap sub-assembly.