Regal 53 SC Owner's Manual page 398

Diesel Generator-Checking Typical Cooling System
The generator features a closed cooling system. The
seawater circulates through separate chambers within the
heat exchanger or manifold to cool the engine coolant.
The seawater mixes with the engine exhaust and exits at
the hull exhaust outlet.
WARNING
!
AVOID SERIOUS INJURY OR DEATH FROM
HOT COOLANT AND STEAM.
STOP THE GENERATOR
AND ALLOW IT TO COOL
BEFORE LOOSENING THE PRESSURE CAP
AND WORKING ON THE GENERATOR.
Maintain the coolant level in the recovery tank at
approximately 1/4 full. Before fi lling the cooling system,
close all petcocks and tighten all hose clamps. Use a solution
of 50% ethylene glycol and 50% clean, softened water
to prevent rust/corrosion build-up and protect against
freezing in colder climates. Add additional coolant solution,
as necessary, to the coolant recovery tank.
Periodically check the coolant level by removing the
pressure cap. Do not rely on the level in the coolant
recovery tank. Add fresh coolant until the level is just below
the overfl ow tube opening.
Note: A coolant solution of 50% ethylene glycol is
required to provide freezing protection (-34 degrees F.)
and overheating protection to (265 degrees F.).
Do not use or mix alcohol or methanol antifreeze or mix
them with the recommended coolant.
Note: If the generator is overheated do not add the
recommended coolant until the generator is cool to prevent
engine or component damage.
Note: After the coolant drains, allow time when refi lling the
coolant for a complete refi ll of the engine water jacket.
A complete fl ushing periodically will keep the cooling
system in optimum condition. Use the service schedule.
To fl ush the cooling system do the following:
1. Open the pressure cap and open petcocks located at the
heat exchanger, engine block, and cooling system, and let
the system drain completely. Remove the pressure cap to
simplify draining.
2. Drain, clean and fl ush the coolant recovery tank.
3. Flush the system with clean water.
4. Fill the system with recommended coolant.
The closed heat exchanger systems use a special pressure
cap that raises the boiling point of the coolant, enabling a
higher operating temperature. If the cap leaks or fails to
hold pressure replace it with one of the same pressure. The
pressure rating is stamped on the cap body.
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Chapter 8