Quick Reference Table For Troubleshooting - Yanmar 4TNV98 Service Manual

When the measured compression pressure is below the limit value, inspect each part by referring to the
table below.
No Item
1 Air Cleaner Element
2 Valve Clearance
3 Valve Timing
Cylinder Head
4
Gasket
Intake/ Exhaust Valve
5
Valve Seat
Piston
6
Piston Ring
Cylinder

Quick Reference Table For Troubleshooting

The following table summarizes the general trouble
symptoms and their causes. If any trouble symptom
occurs, take corrective action before it becomes a
serious problem so as not to shorten the engine
service life.
4TNV98 & 4TNE98 Diesel Engine
Measured Value and Troubleshooting
Cause
Clogged element
Broken element
Defect at element seal portion
Excessive or no clearance
Incorrect valve clearance
Gas leak from gasket
Sticking valve
Gas leak due to worn valve
seat or foreign matter trapped
in
valve
Gas leak due to scratching or
wear
239
Corrective Action
Clean the element.
Replace the element.
Adjust the valve clearance.
Adjust the valve clearance.
Replace the gasket.
Retighten the cylinder head bolts
to the specified
torque.
Replace the intake / exhaust
valve.
Lap the valve seat.
Perform honing and use an
oversized Piston Ring part.
Section 8. Troubleshooting