4TNV98 & 4TNE98 Diesel Engine Section 8. Troubleshooting239Measured Value and TroubleshootingWhen the measured compression pressure is below the limit value, inspect each part by referring to thetable below.No Item Cause Corrective ActionClogged element Clean the element.Broken element1 Air Cleaner ElementDefect at element seal portion Replace the element.2 Valve Clearance Excessive or no clearance Adjust the valve clearance.3 Valve Timing Incorrect valve clearance Adjust the valve clearance.Replace the gasket.4 Cylinder HeadGasket Gas leak from gasket Retighten the cylinder head boltsto the specifiedtorque.Intake/ Exhaust Valve Sticking valve Replace the intake / exhaustvalve.5Valve SeatGas leak due to worn valveseat or foreign matter trappedinvalveLap the valve seat.PistonPiston Ring6CylinderGas leak due to scratching orwearPerform honing and use anoversized Piston Ring part.Quick Reference Table For TroubleshootingThe following table summarizes the general troublesymptoms and their causes. If any trouble symptomoccurs, take corrective action before it becomes aserious problem so as not to shorten the engineservice life.
