Mercury 8.1S Horizon, Product Applications Manual

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Cooling System
90-863758060 AUGUST 2006 Page 7A-11
Factory installed closed cooling systems come filled with an extended life antifreeze. This
coolant allows for a service interval of 5 years or 1000 hours (whichever occurs first), versus
2 years or 400 hours for standard antifreeze. When adding coolant to these systems (i.e.
when filling coolant recovery bottle, installing hot water heater), we recommend that only
an extended-life antifreeze be used. Mixing this coolant with even a small amount of regular
antifreeze will require that the service interval be reduced 2 years. If you are installing
closed cooling kits at your facility, we would also encourage you to use the extended Life
coolant to allow your customer to take advantage of the reduced maintenance costs.
Pre-mixed extended life coolant is available from Quicksilver or can be purchased at most
automotive stores and other locations where antifreeze is sold. Extended-life coolant is
available from Texaco under the name Havoline Extended Life Dex Cool. Prestone also
offers a version of this antifreeze called Extended Life 5/100. Only coolants that state that
they are compatible with Dex Cool should be used. Extended-life coolants can be identified
by their orange color (vs. green for standard coolant) and their corresponding orange cap
on the container.
All antifreeze should be mixed 50/50 with pure water (Quicksilver coolant is already
pre-mixed). If installing closed cooling kits at your facility, be sure to observe the special
filling procedure in the installation instructions.
Closed Cooling System Capacity
8.1S Models 18 liters (19 quarts)
All Other Models 19 liters (20 quarts)
Coolant Recovery System
All Mercury MerCruiser closed cooling systems (except for 8.1S models) are equipped with
a coolant recovery system that must be installed by the boat manufacturer. Coolant
recovery bottle mounting location must meet these requirements:
•
Within approximately 122 cm (4 ft.) of heat exchanger filler neck to allow connection
with tubing provided.
• Even with or slightly above heat exchanger filler neck.
NOTE: This differs from the previous recommendation and has been changed to ensure
that air does not enter the cooling system upon cool down.