Yanmar 4TNV98, Service Manual

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4TNV98 & 4TNE98 Diesel Engine Section 5. Cooling System 207
Disassembly of Engine Coolant Pump
1. Remove the thermostat cover (Figure 8-8, (1)) .
Discard the gasket.
Figure 8-8
2. Remove the thermostat (Figure 8-8, (2)) . Discard
the O-ring. Remove the temperature switch
(Figure 8-8, (3)) and gasket (Figure 8-8, (4)) .
Discard the gasket.
Cleaning and Inspection
Thermostat
1. Check for proper operation of the thermostat.
Place the thermostat (Figure 8-10, (1)) and an
accurate thermometer (Figure 8 -10, (2)) in
warm water.
Figure 8-10
2. Slowly increase the temperature of the water
using an external heat source.
3. The thermostat is operating properly if it starts to
open at the temperature value stamped on the
flange of the thermostat, and fully opens as the
temperature of the water is increased.
Radiator Cap
1. Check for proper operation of the radiator cap.
Install the radiator cap (Figure 8-11, (1)) on a
cooling system tester.
Figure 8-11
2. Apply 10.8 - 14.8 psi (75 - 105 kPa; 0.75 - 1.05
kgf/cm²) to the radiator cap. The radiator cap
relief valve must open within the specified range.