Lexus 2013 IS250 Owner's Manual page 547

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8-2. Steps to take in an emergency
5
Add coolant if necessary.
Water can be used in an emergency
if coolant is unavailable.
6
Start the engine and turn the air conditioning system on to check that
the radiator cooling fan operates and to check for coolant leaks from
the radiator or hoses.
The fan operates when the air conditioning system is turned on immediately
after a cold start. Confirm that the fan is 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 fan may not operate in freezing temperatures.)
7
If the fan is not operating:
Stop the engine immediately and contact any authorized Lexus dealer
or repairer, or another duly qualified and equipped professional.
If the fan is operating:
Have the vehicle inspected at the nearest authorized Lexus dealer or
repairer, or another duly qualified and equipped professional.
IS250_EE(OM53B11E)