Yanmar 3TNV82A-B Service Manual page 131

Periodic Maintenance Procedures
The non-turbo TNV engines use a crankcase
breather system that has a spring-backed
diaphragm (Figure 5-20, (1)) in the valve cover
(Figure 5-20, (2)). When the crankcase pressure
reaches a predetermined value, the diaphragm
opens a passage that allows crankcase fumes to
be routed to the intake manifold.
To inspect the diaphragm and spring
(Figure 5-20, (3)):
1. Remove the bolts retaining the diaphragm cover
(Figure 5-20, (4)).
(4)
Figure 5-20
2. Remove the diaphragm cover, spring,
diaphragm plate (Figure 5-20, (5)) and
diaphragm.
3. Inspect the diaphragm for tears. Inspect the
spring for distortion. Replace components if
necessary.
4. Reinstall the diaphragm, diaphragm plate,
spring and diaphragm cover. Tighten the
diaphragm bolts to specified torque.
TNV DI Service Manual
Failure of the diaphragm and / or spring will cause
the loss of pressure control and allow an excessive
amount of crankcase fumes to be routed to the
intake manifold. This could result in excessive
deposits in the intake system, high engine exhaust
smoke levels, excessive engine oil consumption,
and / or engine run-on due to the burning of the
engine oil.
(3)
(5)
(1)
(2)
0002135
PERIODIC MAINTENANCE
5-41