Mercury 1996 Sable Manual page 308

you have to add more than a quart (liter) at a
time
Engine coolant drain and flush
Proper procedures for a complete coolant drain
and flush of the cooling system can be found in
the Car Service Manual. Following these
recommended procedures will ensure that the
specified coolant level and a 50/50 or
appropriate mixture of coolant and water is
maintained.
Engine coolant refill procedure
When the entire cooling system is drained and
refilled, the following procedure should be used
to ensure a complete fill:
With the engine OFF and cool, remove the
pressure cap, located on the coolant reservoir.
Add a 50/50 mixture of specified coolant and
water to the coolant reservoir. Refer to Refill
Capacities later in this chapter for the correct
amount.
Continue to fill the reservoir until the coolant
is at the top of the cold fill range.
Reinstall the pressure cap until it clicks.
Start and idle the engine until the radiator
upper hose is warm (this indicates the
thermostat is open and coolant is flowing
through the entire system).
Immediately shut off the engine and let cool.
Cautiously remove the pressure cap and add
a 50/50 mixture of specified coolant and
water until the coolant is within the cold fill
range in the coolant reservoir.
Reinstall the pressure cap until a click is
heard and felt.
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