Toyota 2003 Prius Owner's Manual page 234

CAUTION
To prevent burning yourself, do not
remove the radiator cap when the en-
gine is hot.
158.Coolant type selection
Use of improper coolants may damage
your cooling system. Your coolant must
contain ethylene–glycol type coolant for a
proper corrosion protection of your hybrid
system that contains aluminum compo-
nents. We have used "Toyota Genuine
Long Life Coolant" in your Toyota vehicle.
In order to avoid technical problems, we
strongly recommend using "Toyota Genu-
ine Long Life Coolant" or equivalent.
In addition to preventing freezing and sub-
sequent damage to the hybrid system, this
type of coolant will also prevent corrosion.
Further supplemental inhibitors or additives
are neither needed nor recommended.
Read the coolant container for information
on freeze protection. Follow the manufac-
turer's directions for how much to mix
with plain water (preferably demineralized
water of distilled water). The total capacity
of the cooling system is given on page
240 in Section 9.
We recommend to use 50% solution for
your Toyota, to provide protection down to
about –35 C (–31 F). When it is extremely
cold, to provide protection down to about
–50 C (–58 F), 60% solution is recom-
mended. Do not use more than 70% solu-
tion for better coolant performance.
NOTICE
Do not use alcohol type antifreeze or
plain water alone.
The engine cooling system is integral to
maximizing performance of your Toyota
vehicle. In line with this, it is strongly
recommended that you use "Toyota Genu-
ine Long Life Coolant" for protecting the
system, as it is an ethylene–glycol based
premium antifreeze coolant with excellent
corrosion protection properties that has
been specifically formulated for use in
Toyota vehicles.
Please contact your Toyota dealer for fur-
ther details of the "Toyota Genuine Long
Life Coolant" range.
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