Troubleshooting
1. Dirt in oil
Dirty oil damages the turbocharger by causing heavy scoring of critical bearing surfaces. To avoid damage, oil and filters should be of a quality recommended by OEM. These should be changed when new turbocharger is fitted and at regular intervals according to the engine manufacturers specification. Dirty oil damage may be caused by:
A. Block, damaged or poor quality oil filter
B. Dirt introduced during servicing
C. Engine wear or manufacturing debris
D. Malfunctioning oil filter by-pass valve
E. Degraded lubrication oil
2. insufficient oil supply
If turbocharger oil flow is restricted over longer periods the turbocharger bearing system will show signs of heat discoloration as well as polished and burnished surfaces. This type of failure is commonly known as oil starvation. The causes as below:
A. Re-fitting a turbocharger without adequate priming
B. Non-use for a long time
C. Broken oil feed pine
D. Low engine oil pressure due to malfunctioning lubrication system
E. Low or no oil in sump
F. The use of sealants can result in restricting the oil flow
3. Over heating
Failure from excessive exhaust temperatures or shutting the engine down without allowing time for the turbocharger to cool down results in carbon build-up. It is recommend that you idle the engine for 2 or 3 minutes to cool the bearing system before shutting down. Turbine end heat soak into the bearing housing results in oil carbonization and corrosion of the bearing system. The main cause as following:
A. Blocked air cleaner/excessive intake restriction
B. Hot shutdown of engine
C. Degraded oil quality carbonizing in service
D. Infrequent oil change intervals causing oil breakdown in service
E. Air and gas leaks
F. Faulty fuel injector pump or injector.
3. smoking
Impact damage caused by foreign material entering the turbine housing or compressor housing is visible on the turbine and compressor wheels. Not allow to operate the turbocharger with damaged blades as the root balance will be affected and this could impact its service life.
4. low power
Air inlet restriction prevents the engine from breathing as designed; this increases the engine operating temperature. An air leak in the compressor outlet, or a partially or blocked intercooler would restrict the engine breathing.
5. Noisy
Often the noise comes from air or gas leakage, due to pre-turbine exhaust gas or and air leaks. Check all joints, if noise continues, check turbocharger clearances and wheels for housing contact
6. Seized/Sluggish
If the turbocharger rotor assembly has seized or is tight to rotate, this is often due to lubricating oil degradation and insufficient or an intermittent drop in oil pressure can cause the rotor to seize as can introducing dirt into the lubricating oil.
7. worn/excessive clearance
A turbocharger has specific axial and radial rotor clearances. These are sometimes mis-diagnosed as worn bearings. If the clearances are out of specification the cause could be attributed to a lubricating oil problem, e.g. insufficient oil, dirt ingress, oil contamination with coolant. |