Ford 1996 Aerostar Manual page 268

3. Turn the heater (temperature and mode
selection) knobs to maximum heat positions
and operate the engine at fast idle
(approximately 2000 RPM) for three to four
minutes.
4. Shut off the engine and allow the engine to
cool. Cover the radiator cap with a thick
cloth and cautiously remove it. Step back
while the pressure releases.
5. Add the engine coolant mixture to a level
approximately 1 to 1 1/2 inches (38 mm)
below the filler neck seat.
6. Reinstall the radiator cap fully and back off
to the first stop. Once again, turn the engine
at fast idle until the upper radiator hose is
warm and the thermostat is open.
7. Finally, check the radiator and add more
engine coolant if needed, following the
procedures noted above. Reinstall the
radiator cap securely, when finished.
8. If more engine coolant is necessary, remove
the small plug from the top of the engine
coolant recovery reservoir (not the large cap
of the windshield washer reservoir) and add
1.1 quarts (1 liter) of the 50/50 engine
coolant mixture. Replace the plug in its
original position.
NOTE: Due to air being trapped in the 4.0L
engine cooling system, it is not
unusual to experience a 4 to 7 ounce
(120 to 210 ml) coolant loss up to 7,500
miles (12,000 km) after initial system
fill.
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