Yanmar 4TNE98, Service Manual, Page: 207 / 246

4TNV98 & 4TNE98 Diesel Engine Section 5. Cooling System 205
Engine Coolant System Check
Check the engine coolant system for leakage.
1. With the radiator properly filled, install a cooling
system tester (Figure 8-3, (1)) .
Figure 8-3
2. Apply 10.8-14.8 psi (75-105 kPa; 0.75-1.05
kgf/cm²) to the cooling system. If the pressure
reading drops, the engine coolant system is
leaking. Identify the source of the leak and repair
it.
Engine Coolant Pump
Removal of Engine Coolant Pump
Verify the condition of the engine coolant pump
before disassembling it from the engine. Check the
engine coolant pump shaft bearing for abnormal
noise, sticking, excessive play and water leakage.
Replace the coolant pump if any of these conditions
are present.
CAUTION
If the engine coolant pump must be replaced,
replace the engine coolant pump as an
assembly only. Do not attempt to repair the
engine coolant pump or replace individual
components.
IMPORTANT
Make sure the engine and engine coolant are
not hot.
1. Before removing the engine coolant pump or
thermostat, it will be necessary to drain the
engine coolant. Drain the coolant into a clean
container if the coolant is to be reused.
Otherwise, properly dispose of the coolant.
2. Remove the radiator cap (Figure 8-4, (1)).
3. Remove the drain plug or open the drain cock
(Figure 8-4, (1)) at the lower portion of the
radiator and drain the coolant.
Figure 8-4
4. Drain the coolant from the engine block.
• On models equipped with an oil cooler, remove
the coolant hose (Figure 8-5, (1)) at the oil
cooler.
Figure 8-5