Regal 53 SC Owner's Manual page 480

GENERAL NOTES ON ANTIFREEZE
Engine cooling fl uids must be replaced with a marine
antifreeze solution; mix antifreeze according to directions
for the lowest expected temperature. The above method
is much more reliable than just draining the engines and
manifolds because sometimes pockets of water can form
which can freeze in cold temperatures and cause engine
damage. Draining the system fosters rust in engine parts.
Historically, antifreeze was originally made with methanol.
It was because of its chemical nature to escape into the
atmosphere and a high corrosion factor on engine metals
that it was replaced.
Today, ethylene glycol is used in auto and marine engine
applications because of its positive thermal properties. On
the downside ethylene glycol contains silicate rust inhibitors
that can clog up marine heat exchanger surfaces. This is
why it is so important to follow the engine manufacturer
maintenance schedules which include changing the
antifreeze periodically. In addition, the unpleasant odor of
antifreeze is caused by tolyltriazole which also contributes
to it being environmentally hazardous. Notwithstanding,
ethylene glycol is poisonous to the human body along
with animals. Therefore, it cannot be used in potable
marine water systems.
Propylene glycol is considerably less toxic and retail
products are labeled as "non-toxic antifreeze". It is the
product of choice for marine water and waste tanks in
freezing climates. It is available at marinas, RV dealerships,
and at retail marine outlets.
NOTICE
USE A SPECIAL NON-TOXIC ANTIFREEZE
IN THE FRESH WATER & WASTE SYSTEM
WHICH IS AVAILABLE AT RV AND
MARINE DEALERS.
DO NOT USE AN AUTOMOTIVE
TYPE ANTIFREEZE.
IT CAN BE HIGHLY
POISONOUS AND CORROSIVE.
Storage & Winterization
ZEUS DRIVE UNITS
Since the drive units are located under the vessel it makes
good sense to use a Regal yacht dealer to ensure the units
are winterized. The yacht dealer can check all drive related
systems along with the propellers. This is a great time to
have the propellers checked for balance and nicks.
Also, when the the propellers and hardware are off the
propeller shaft and seals can be checked for vacuum and
pressure along with touching up the drive unit.
Seasonal inspections are a great time to inspect the anodes
located on the hull and drive units. Replace as necessary.
Refer to your Cummins and Zeus operator's manual
for specific drive information and maintenance
schedules.
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