Indmar Premium 400, Operator'S Manual, Page: 92 / 124

8-4
SECTION EIGHT
Seawater Cooling System Preparation
Your Indmar engine is equipped with a cooling system that uses a
50/50 propylene glycol antifreeze and water mixture in the engine
block and raw water in the heat exchanger and exhaust system. If
the boat is kept in an area where the temperature falls below the
freezing point of water (32°F or 0°C), the cooling system must be
winterized to prevent freeze damage to the engine. Do not leave
the boat in the water during freezing conditions.
The protection level of the antifreeze must be tested using a
refractometer type antifreeze tester that is designed to test
propylene glycol antifreeze. These testers are available at
automobile parts stores and can also be found on many websites
that sell automotive related tools and equipment. Follow the
instructions that come with the tester and make sure the antifreeze
in the engine will protect to lower than the lowest temperature that
your part of the world experiences.
Cylindrical Heat Exchanger Winterization/Draining
Points
OTE: N There are sacrificial anodes in the heat exchanger
and in the transmission drain that should be inspected
annually and replaced as needed. Contact your dealer for
assistance.
Raw Water Drain Points
The raw water side of the cooling system is protected from
freezing by draining the raw water from the system. The raw water
drain points are indicated on the winterization drain point drawings
on the following pages. There are also blue stickers attached to the
engine at the drain points and blue plastic wing nut style plugs to
help you locate them and make them easy to remove without tools.