Ford 2003 Mustang Owner's Manual page 152

Maintenance and care
Plain water may be added in an emergency, but you
must replace it with a 50/50 mixture of coolant and
distilled water as soon as possible.
Check the coolant level in the coolant reservoir the
next few times you drive the vehicle. If necessary,
add enough of a 50/50 mixture of coolant and
distilled water to bring the liquid level into the cold
fill range on the reservoir.
Never remove the coolant reservoir cap
while the engine is running or hot.
If you must remove the coolant reservoir cap, follow
these steps to avoid personal injury:
1. Before you remove the cap, turn the engine off
and let it cool.
2. When the engine is cool, wrap a thick cloth
around the cap. Slowly turn cap counterclockwise
until pressure begins to release.
3. Step back while the pressure releases.
4. When you are sure that all the pressure has been
released, use the cloth to turn it counterclockwise
and remove the cap.
Change your engine coolant according to the
appropriate schedule listed in the Scheduled
Maintenance Guide.
Recycled engine coolant
Ford Motor Company recommends that Ford and
Lincoln-Mercury dealers use recycled engine coolant
produced by Ford-approved processes.
Not all coolant recycling processes produce coolant
which meets Ford specification ESE-M97B44–A, and
use of such coolant may harm engine and cooling
system components.
Always dispose of used automotive fluids in a
responsible manner. Follow your community's
regulations and standards for recycling and disposing
of automotive fluids.
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