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Turbocharger bearing failures can cause large quantities of oil to enter the air inlet and exhaust systems. Loss of engine lubricant can result in serious engine damage.Minor leakage of a turbocharger housing under extended low idle operation should not cause problems as long as a turbocharger bearing failure has not occurred.When a turbocharger bearing failure is accompanied by a significant engine performance loss (exhaust smoke or engine rpm up at no load), do not continue engine operation until the turbocharger is repaired or replaced.
An inspection of the turbocharger can minimize unscheduled downtime. Also, the chance for potential damage to other engine parts is reduced.Note: Turbocharger components require clearances that are precise. The turbocharger cartridge must be balanced due to high rpm.The following conditions can cause the turbocharger to be out-of-balance:
The buildup of deposits
Chipping and/or flaking of depositsIf the turbocharger must be removed for inspection, use caution. Do not break deposits from the turbine wheel. Do not attempt to clean the turbine wheel. For options regarding removal, installation, repair and replacement, see the Service Manual or consult your Cat dealer.
Remove the exhaust outlet piping and remove the air inlet piping from the turbocharger. Visually inspect the piping for the presence of oil.
Turn the compressor wheel and the turbine wheel by hand. The assembly should turn freely. Inspect the compressor wheel and the turbine wheel for contact with the turbocharger housing. There should not be any visible signs of contact between the turbine wheel or compressor wheel and the turbocharger housing. If there is any indication of contact between the rotating turbine wheel or the compressor wheel and the turbocharger housing, the turbocharger should be reconditioned.
Check the compressor wheel for cleanliness. If only the blade side of the wheel is dirty, dirt and/or moisture is passing through the air filtering system. If oil is found only on the back side of the wheel, there is a possibility of a failed turbocharger oil seal. The presence of oil may be the result of extended engine operation at low idle. The presence of oil may also be the result of a restriction of the line for the inlet air (plugged air filters). A restriction of the line for the inlet air causes the turbocharger to slobber.Note: Deposits can accumulate on the turbine wheel. The turbine wheel will become unbalanced when the deposits flake off. The turbocharger cartridge must be replaced when the turbine wheel becomes unbalanced. Removing deposits from the housing will prevent wear on the blades of the turbine wheel.
Inspect the turbine wheel for deposits. If deposits of 1.6 mm (0.0625 inch) thickness are found or if the turbine is in contact with the housing, the turbocharger must be disassembled and cleaned. Removal of these deposits can be difficult.
Inspect the bore of the turbine housing for corrosion and deposits.
Clean the turbocharger compressor housing with standard shop solvents and a soft bristle brush.
Check the clearances of the turbocharger bearing. Compare the clearances to the Service Manual, "Specifications". If the clearances are not within the specifications, the turbocharger must be repaired.
Fasten the air inlet piping and the exhaust outlet piping to the turbocharger housing.