Lexus RX (RX 350L, RX450h) 2016-2025 Owners Manual: If your vehicle overheats

The following may indicate that your vehicle is overheating.

• The needle of the engine coolant temperature gauge enters the red zone, or a loss of hybrid system power is experienced. (For example, the vehicle speed does not increase.)
• "Engine Coolant Temp High Stop in a Safe Place See Owner's Manual" or "Hybrid System Overheated Reduced Output Power" is shown on the multi-information display.
• Steam comes out from under the hood.

Correction procedures

■ "Engine Coolant Temp High Stop in a Safe Place See Owner's Manual" is shown on the multi-information display

1. Stop the vehicle in a safe place and turn off the air conditioning system, and then stop the hybrid system.

2. If you see steam: Carefully lift the hood after the steam subsides.

If you do not see steam: Carefully lift the hood.

3. After the hybrid system has cooled down sufficiently, inspect the hoses and radiator core (radiator) for any leaks.

1. Radiator
2. Cooling fans

If a large amount of coolant leaks, immediately contact your Lexus dealer.

4. The coolant level is satisfactory if it is between the "FULL" and "LOW" lines on the reservoir.

1. Reservoir
2. "FULL" line
3. "LOW" line
4. Radiator cap

5. Add coolant if necessary.

Water can be used in an emergency if coolant is unavailable.

6. Start the hybrid system and turn the air conditioning system on to check that the radiator cooling fans operate and to check for coolant leaks from the radiator or hoses.

The fans operate when the air conditioning system is turned on immediately after a cold start. Confirm that the fans are operating by checking the fan sound and air flow. If it is difficult to check these, turn the air conditioning system on and off repeatedly. (The fans may not operate in freezing temperatures.)

7. If the fans are not operating: Stop the hybrid system immediately and contact your Lexus dealer.

If the fans are operating: Have the vehicle inspected at the nearest Lexus dealer.

8. Check if "Engine Coolant Temp High Stop in a Safe Place See Owner's Manual" is shown on the multi-information display.

If the message does not disappear: Stop the hybrid system and contact your Lexus dealer.

If the message is not displayed: Have the vehicle inspected at the nearest Lexus dealer.

■ If "Hybrid System Overheated Reduced Output Power" is shown on the multi-information display

1. Stop the vehicle in a safe place.

2. Stop the hybrid system and carefully lift the hood.

3. After the hybrid system has cooled down, inspect the hoses and radiator core (radiator) for any leaks.

1. Radiator
2. Cooling fans

If a large amount of coolant leaks, immediately contact your Lexus dealer.

4. The coolant level is satisfactory if it is between the "FULL" and "LOW" lines on the reservoir.

1. Reservoir
2. "FULL" line
3. "LOW" line

5. Add coolant if necessary.

Water can be used in an emergency if coolant is unavailable.

6. Start the hybrid system and check if "Hybrid System Overheated Reduced Output Power" is shown on the multi-information display.

If the message does not disappear: Stop the hybrid system and contact your Lexus dealer.

If the message is not displayed: Have the vehicle inspected at the nearest Lexus dealer.

WARNING

■ To prevent an accident or injury when inspecting under the hood of your vehicle Observe the following precautions.

Failure to do so may result in serious injury such as burns.

• If steam is seen coming from under the hood, do not open the hood until the steam has subsided. The engine compartment may be very hot.
• After the hybrid system has been turned off, check that the "READY" indicator is off.

  When the hybrid system is operating, the gasoline engine may automatically start, or the cooling fans may suddenly operate even if the gasoline engine stops. Do not touch or approach rotating parts such as the fans, which may lead to fingers or clothing (especially a tie, a scarf or a muffler) getting caught, resulting in serious injury.

• Do not loosen the radiator cap and the coolant reservoir caps while the hybrid system and radiator are hot.

  High temperature steam or coolant could spray out.

NOTICE

■ When adding engine/power control unit coolant Add coolant slowly after the hybrid system has cooled down sufficiently. Adding cool coolant to a hot hybrid system too quickly can cause damage to the hybrid system.

■ To prevent damage to the cooling system Observe the following precautions:

• Avoid contaminating the coolant with foreign matter (such as sand or dust etc.).
• Do not use any coolant additive.