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Turbocharger Troubleshooting and Diagnostics

Turbocharger Failure Diagnosis

Loss of power, excess smoke, high fuel consumption, overheating, high exhaust temperatures and oil leakages from the turbocharger are all symptoms that could indicate turbocharger malfunction. However, these faults are often wrongly attributed to the turbocharger because defects in other components can produce the same symptoms. The turbocharger performance can only be impaired by mechanical damage or blockage caused by dirt.

This checklist provides a comprehensive list of the most common symptoms related to turbocharger failure. BEFORE replacing a turbocharger, verify the problem by consulting the chart below. If after taking the appropriate action, problems still persist, please contact your nearest Diesel USA Group location for advice.

Possible Failure Diagnosis Engine Running Hot Poor Transient Response Smoke Engine Lacks Power Black Exhaust Smoke Blue Exhaust Smoke High Oil Consumption Turbocharger Noisy Cyclic Sound from the Turbocharger Oil Leak from Compressor Seal Oil Leak from Turbine Seal
Dirty air cleaner
Clean or replace element according to manufacturer’s recommendations
Restricted compressor intake duct
Remove restriction or replace damaged parts as required
Restricted air duct from compressor to intake manifold
Replace seals, gaskets or tighten fasteners as required
Restricted intake manifold
Refer to engine manufacturer’s manual and remove restriction
Air leak in feed from air cleaner to compressor
Replace seals, gaskets or tighten fasteners as required
Air leak in feed from compressor to intake manifold
Replace seals, gaskets or tighten fasteners as required
Air leak between intake manifold and engine
Refer to engine manufacturer’s manual and replace gaskets or tighten fasteners as required
Foreign object in exhaust manifold (from engine)
Refer to engine manufacturer’s manual and remove obstruction
Restricted exhaust system
Remove restriction or replace damaged parts as required
Exhaust manifold cracked, gaskets blown or missing
Refer to engine manufacturer’s manual and replace gaskets or damaged parts as required
Gas leak at turbine inlet/exhaust manifold joint
Replace gasket or tighten fasteners as required
Gas leak in ducting after turbine outlet
Refer to engine manufacturer’s manual and repair leak
Restricted turbocharger oil drain line
Remove restriction or replace damaged parts as required
Restricted engine crankcase breather
Refer to engine manufacturer’s manual, clear restriction
Turbocharger bearing housing sludged or coked
Change engine oil and oil filter, overhaul or replace turbocharger as required
Fuel injection pump or fuel injectors incorrectly set
Refer to engine manufacturer’s manual and replace or adjust faulty components as required
Engine valve timing incorrect
Refer to engine manufacturer’s manual for correct settings and adjust as required
Worn engine piston rings or liners
Refer to engine manufacturer’s manual and repair as required
Burnt valves and/or pistons
Refer to engine manufacturer’s manual and repair as required
Excessive dirt build-up on impeller and/or diffuser vanes
Clean in accordance with the appropriate manufacturer repair manual
Turbocharger damaged
Find and correct cause of failure, repair or replace turbocharger as necessary
Failed diaphragm
Replace using correct Actuator Service Kit
Siezed valve
Free valve/replace complete turbine housing sub-assembly
Leaking hose
Replace hose and clips
Wastegate mechanism set incorrectly
Contact our Diesel USA Group location you for details on proper settings
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