BALL BEARING 3K2518 - Caterpillar

The oil may be present on the outside of the air line or on the inside of the air line. The presence of oil does not indicate that the turbocharger must be replaced. In most cases, the turbocharger is okay. Usually, another problem is causing oil to leak from the turbocharger. The root cause must be identified and repaired in order to stop the oil from leaking from the turbocharger.Probable Causes
There is excessive crankcase pressure (caused by a plugged crankcase breather or a plugged crankcase fumes fitting).
The engine oil contains fuel.
There is a leak in the air lines between the turbocharger and the engine inlet.
The engine has high back pressure.
There is high flow of Clean Gas Induction (CGI).
There is a problem with the turbocharger.Troubleshooting Procedure
The following list provides a way to classify the oil leak. The amount of oil determines the troubleshooting that must be performed.Heavy Oil Leak - There is oil on the outside of an air line. The oil is leaking from an air line connection.Moderate Oil Leak - Oil is not leaking from an air line connection. Oil has collected on the inside of an air line. The oil drips from the air line when the air line is disconnected.Minor Oil Leak - Oil is not leaking from an air line connection. Oil has collected on the inside of an air line. The oil does not drip from the air line when the air line is disconnected.Slight Oil Leak - Oil is not leaking from an air line connection. However, there are streaks of oil on the inside of an air line. A slight oil leak from the turbocharger is normal. No troubleshooting is required if there is a slight oil leak.
No troubleshooting is required if there is a slight oil leak. Wipe the inside of the air line if there is a slight oil leak.
Inspect the following components if the oil leak is heavy, moderate, or minor.Turbocharger Compressor Housing - Inspect the housing for signs of wear and of rubbing. If the turbocharger compressor housing has signs of wear or of rubbing, replace the turbocharger. Continue with this procedure after the turbocharger has been replaced.Turbocharger Compressor Wheel - Inspect the outside edges of the compressor wheel for signs of wear and of rubbing. If the compressor wheel has signs of wear or of rubbing, replace the turbocharger. Continue with this procedure after the turbocharger has been replaced.
Check for the logged diagnostic codes that are listed in Table 1.
Table 1
Diagnostic Trouble Codes That Relate to Oil in an Air Line    
Suspect Parameter Number (SPN)    Failure Mode Identifier (FMI)    Description    
102     18     Engine Intake Manifold #1 Pressure : Low