
COOLING SYSTEM
Repair
7-8
BY Service Manual
© 2009 Yanmar Marine International
Test Thermostat
1. The design temperature for the thermostat is
stamped into the thermostat body. Find and
record this number.
2. Immerse the thermostat into a container of
water. Suspend it so that it does not come into
contact with the walls or bottom of the
container.
3. Slowly heat the water and monitor the
temperature with a thermometer. Stir the water.
4. Check that the thermostat begins to open at the
specified temperature, and that it is fully open at
the temperature given in the specifications.
If the test results are not within specification,
replace the thermostat.
Specifications
REPAIR
Drain and Refill Seawater Cooling
System
Note: 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.
1. Open the lower seawater drain cock
(Figure 7-4, (1)) located in the piping between
the seawater pump and hydraulic oil cooler.
Allow to drain.
Figure 7-4
Figure 7-4
2. Open the drain cock (Figure 7-4, (2)) on the
bottom of the charge air cooler.
3. Loosen the seawater pump cover
(Figure 7-4, (3)) to allow water to drain. See
Seawater Pump on page 7-18.
4. When water has drained, install cover and
tighten bolts. NOTICE: Be sure O-ring is in
place in the groove of housing.
5. Remove anodes from the engine heat
exchanger (Figure 7-4, (4)) and charge air
cooler (Figure 7-4, (5)) and allow water to drain
from housings.
Item
Marking
Starts
Opening
Fully Open
Thermostat
Opening
88°C
88°C
(190°F)
96°C (205°F)
000662
8
(1)
(2)
(5)
(4)
(
3
)