Lexus GS430 User Manual page 559

Look at the see−through coolant reservoir when the
engine is cold. The coolant level is satisfactory if it is
between the"FULL" and "LOW" lines on the reservoir. If
the level is low, add the coolant. (For the coolant type, see
"Coolant type selection" described below.)
The coolant level in the reservoir will vary with engine
temperature. However, if the level is on or below the "LOW"
line, add coolant. Bring the level up to the "FULL" line.
If the coolant level drops within a short time after replenishing,
there may be a leak in the system. Visually check the radiator,
hoses, engine coolant filler cap, radiator cap and drain cock
and water pump.
If you can find no leak, have your Lexus dealer test the cap
pressure and check for leaks in the cooling system.
CAUTION
To prevent burning yourself, do not remove the radiator
cap when the engine is hot.
Coolant type selection
Use of improper coolants may damage your engine cooling
system.
Only use "Toyota Super Long Life Coolant" or similar high
quality ethylene glycol based non−silicate, non−amine,
non−nitrite, and 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.)
For the U.S.A.—"Toyota Super Long Life Coolant" is a mixture
of 50% coolant and 50% deionized water. This coolant
provides protection down to about −35_C (−31_F).
For Canada—"Toyota Super Long Life Coolant" is a mixture of
55% coolant and 45% deionized water. This coolant provides
protection down to about −42_C (−44_F).
NOTICE
Do not use plain water alone.
ENGINE
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