Ford 1996 Aerostar Manual page 267

Engine Coolant Drain and Flush
To drain your vehicle's engine coolant:
1. Turn off the engine and let it cool. Fully
depressurize the engine cooling system by
covering the radiator cap with a thick cloth
and turning it slowly counterclockwise to the
first stop. Step back while the pressure
releases.
2. Remove the cap.
3. Attach a small hose to the drain tube at the
bottom of the radiator.
4. Let the engine coolant drain into a suitable
container. Disconnect the lower radiator hose
at the radiator connector and drain any
remaining engine coolant into a container.
5. Reconnect the lower radiator hose and close
the radiator drain cock.
Proper procedures for flushing the cooling
system can be found in the Service Manual.
Engine coolant refill procedure
After you have drained the engine cooling
system:
1. Fill the radiator with a 50/50 mixture of the
specified engine coolant concentrate and
water. Allow several minutes for trapped air
to escape (bubble out) and for engine coolant
to flow through the radiator.
2. Replace the radiator cap to its fully installed
position, then back off to the first stop. This
will prevent high pressure from building up
in the cooling system during this part of the
fill procedure.
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