Draining the Seawater Cooling
System
CAUTION! DO NOT drain the coolant
system. A full coolant system will
prevent corrosion and frost damage.
CAUTION! If seawater is left inside of the
engine, it may freeze and damage parts
of the cooling system when the ambient
temperature is below 0°C (32°F).
NOTICE: If water fails to drain from any open
drain cock or port, remove the cock
completely and probe the opening with a
small piece of wire to loosen debris.
0006575
(1)
(4)
(3)
(2)
Figure 1
WARNING! NEVER drain the seawater
cooling system if the engine is hot.
Steam and hot fluid will escape and
seriously burn you. Allow the engine to
cool before attempting to opening the
drain cocks.
1. Open the lower seawater drain cock
(Figure 1, (3)) located in the piping
between the seawater pump and
hydraulic oil cooler. Allow to drain.
2. Open the drain cock (Figure 1, (4)) on
the bottom of the charge air cooler.
3. Remove the seawater pump cover. See
your authorized Yanmar dealer or
distributor.
4. Remove zinc anodes from the heat
exchanger (Figure 1, (2)) and charge
air cooler (Figure 1, (1)) and allow
water to drain from housings.
5. Inspect condition of zinc anodes. Install
anodes. See Replacing the Zinc
Anodes on page 53. NOTICE: Do not
use thread sealer or thread sealing tape
when installing zinc anodes. Anodes
must make good metal-to-metal contact
to perform properly.
6. Close all drain cocks.
LONG-TERM STORAGE
70
BY Series Operation Manual
© 2008 Yanmar Marine International
