. OPERATION TROUBLESHOOTING Problem Main causes Remedy Exhaust gas occasionally turns black Clogged air cleaner element Clean or replace, see WHEN REQUIRED ( Replace injector) ( See defective compression above) ( Clean or replace turbocharger) Defective injector Defective compression Defective turbocharger Combustion noise occasionally makes breathing sound Defective nozzle ( Replace nozzle) Abnormal noise generated (combustion or mechanical) Low grade fuel being used Overheating Change to specified fuel Refer to "Water temperature gauge is in red range" as above ( Replace muffler) ( Adjust valve clearance) Damage inside muffler Excessive valve clearance 3 - 176