Ford Mercury Villager 1997 Owner's Manual page 291

Check the coolant level in the coolant recovery reservoir the next
few times you drive the vehicle. If necessary, add enough of a
50/50 mixture of coolant and water to bring the liquid level to the
fill line on the reservoir.
Never remove the coolant recovery cap while the engine is
running or hot.
If you must remove the coolant recovery cap, follow these steps
to avoid personal injury caused by escaping steam or engine
coolant:
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 to the first stop.
3. Step back while the pressure releases.
4. When you are sure that all the pressure has been released, use
the cloth to press the cap down, turn it counterclockwise, and
remove it.
Use Ford Premium Engine Coolant E2FZ-19549-AA (in Canada,
Motorcraft CXC-8-B) or an equivalent premium engine coolant that
meets Ford Specification ESE-M97B44-A. Ford Premium Engine
Coolant is an optimized formula that will protect all metals and
rubber elastomers used in Ford cooling systems for 4 years or
50,000 miles (80,000 km).
Do not use alcohol or methanol antifreeze or any engine coolants
mixed with alcohol or methanol antifreeze. Do not use
supplemental coolant additives in your vehicle. These additives
may harm your engine cooling system. The use of an improper coolant
may void the warranty of your vehicle's engine cooling system.
Maintenance and Care
WARNING
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