Yanmar 4TNE98, Service Manual

Page: 84 / 246

4TNV98 & 4TNE98 Diesel Engine Section 3. Engine 82
Disassembly of 4-Valve Cylinder Head
Prepare a clean, flat working surface on a
workbench large enough to accommodate the
cylinder head assembly. Discard all gaskets, O-rings
and seals. Use new gaskets, O-rings and seals on
reassembly of the cylinder head.
1. Drain the coolant from the engine into a suitable
container. See Drain, Flush and Refill Cooling
System with New Coolant on page 163.
CAUTION
Identify all parts and their location using an
appropriate method. It is important that all parts
are returned to the same position during the
reassembly process.
2. Remove the high pressure fuel injection lines
(Figure 6-37, (1)) . See Removal of Fuel Injectors
on page7-31.
Figure 6-37
CAUTION
Remove or install the high-pressure fuel
injection lines as an assembly whenever
possible. Disassembling the high-pressure fuel
injection lines from the retainers or bending any
of the fuel lines will make it difficult to reinstall
the fuel lines.
3. Disconnect the fuel return hose (Figure 6-37, (2))
from the cylinder head.
4. Disconnect the hoses (Figure 6-37, (3)) from the
cold start device on the fuel injection pump.
5. Remove the turbocharger-to-intake manifold hose
(Figure 6-38, (1)) (if equipped).
6. Disconnect the electrical wire from the intake air
heater (Figure 6-38, (12)) .
7. Remove the intake manifold bolts (Figure 6-38,
(11)) . Remove the intake manifold (Figure 6-38,
(10)) . Discard the intake manifold gasket (Figure
6-38, (9)) .
8. Remove the exhaust manifold bolts (Figure 6-38,
(7)) . Remove the exhaust manifold (Figure 6-38,
(6)) with the turbocharger attached. Discard the
exhaust manifold gasket. (Figure 6-38, (5)) .