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

Replacement

REPLACEMENT

CAUTION / NOTICE / HINT

CAUTION:

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

PROCEDURE

1. DRAIN ENGINE COOLANT

CAUTION:

Do not remove the radiator cap sub-assembly or radiator drain cock plug 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 2 bolts and clip.

(b) Pull down the No. 3 engine under cover.

(c) Connect a hose with an inside diameter of 9 mm (0.354 in.) to the radiator drain cock as shown in the illustration.

*1 No. 3 Engine Under Cover *a Hose

(d) Loosen the radiator drain cock plug.

(e) Loosen the cylinder block drain cock plug.

(f) Remove the radiator cap sub-assembly. Then drain the engine coolant.

HINT:

Collect the engine coolant in a container and dispose of it according to the regulations in your area.

(g) Tighten the radiator drain cock plug by hand.

(h) Tighten the cylinder block drain cock plug.

Torque:

12.7 N·m {130 kgf·cm, 9 ft·lbf}

(i) Disconnect the hose from the radiator drain cock.

(j) Install the 2 bolts and clip.

2. ADD ENGINE COOLANT

(a) Slowly fill the radiator assembly with engine coolant.

Specified Capacity:

NOTICE:

Do not substitute plain water for engine coolant.

HINT:

LEXUS vehicles are filled with TOYOTA SLLC at the factory. In order to avoid damaging 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).

(b) Remove the reserve tank cap.

(c) Slowly pour engine coolant into the radiator reserve tank assembly until it reaches the FULL line.

(d) Squeeze the No. 1 radiator hose and No. 2 radiator hose several times by hand, and then check the level of the engine coolant.

If the engine coolant level is low, add engine coolant.

(e) Install the radiator cap sub-assembly and reserve tank cap.

(f) Bleed air from the cooling system.

(1) Warm up the engine until the water inlet with thermostat sub-assembly opens. While the water inlet with thermostat sub-assembly is open, circulate the engine coolant for several minutes.

HINT:

The water inlet with thermostat sub-assembly open timing can be confirmed by squeezing the No. 2 radiator hose by hand, and sensing vibrations when the engine coolant starts to flow inside the No. 2 radiator hose.

(2) Maintain the engine speed at 2500 to 3000 rpm.

(3) Squeeze the No. 1 radiator hose and No. 2 radiator hose several times by hand to bleed air from the cooling system.

CAUTION:

When squeezing the No. 1 radiator hose and No. 2 radiator hose:

(g) Stop the engine, and wait until the engine coolant cools down.

(h) Add engine coolant to the FULL line on the radiator reserve tank assembly.

3. INSPECT FOR COOLANT LEAK

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