Yanmar 1GM User Manual page 187

COOLING SYSTEM
Hose
Heat exchanger
O-rings
heating. It is recommended to remove and clean the heat
exchanger whenever the coolant is changed. Refer to Fig-
ure 36.
1. Drain both sections of the cooling system. Refer to
Chapter Four. Loosen the hose clamps and disconnect the
seawater inlet and outlet hoses from the end caps (Figure
37).
2. Remove the end cap retaining bolts.
3. Remove the heat exchanger end caps. Remove and dis-
card the gaskets.
181
Index
pin
End ' _ _
~~I~End
~1 -~
4. Remove the heat exchanger (Figure 38).
NOTE
If
the heat exchanger is plugged or contains
heavy scale deposits, take it to a marine
dealership or automotive radiator repair
shop for proper cleaning to avoid potential
damage to the unit.
5. Clean all gasket residue from the end caps and heat
exchanger sealing surfaces.
6. Insert an appropriate-size wire brush into each passage
in the heat exchanger. Work the brush back and forth with
a vigorous motion, but work carefully to avoid damage to
the soldered joints.
7. Remove the brush, hold the heat exchanger vertically
and blow loosened particles out with compressed air.
8. Repeat Step 6 and Step 7 as necessary to remove as
much of the accumulated deposits as possible.
9. Reinstall the heat exchanger by reversing the removal
procedure. Position the heat exchanger so the index pins
(Figure 39) in both ends fit in the holes in the end caps.
10. Fill the freshwater section with coolant. Refer to
Chapter Three. Start the engine and check for leaks.
SEAWATER COOLING SYSTEM MAINTENANCE
The only maintenance required for the seawater cooling
system is periodic flushing. Refer to Chapter Three.