BOLT 4F3648 - Caterpillar

Periodic inspection and cleaning is recommended for the turbocharger compressor housing (inlet side). Since the crankcase fumes are ingested through the inlet air system, oil and combustion by-products may collect in the turbocharger compressor.This buildup, over time, can contribute to loss of engine power, increased black smoke, and overall loss of engine efficiency. This buildup is only a possible contributor to these conditions.Operating the engine until the turbocharger fails can severely damage the turbocharger's compressor wheel and/or the engine. Damage to the turbocharger compressor wheel could allow parts from the compressor wheel to enter the engine cylinder, causing additional damage to the pistons, the valves, and the cylinder head.
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 will 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 speed up at no load), DO NOT continue engine operation until the turbocharger is repaired or replaced.
Cleaning, inspecting, and checking the turbocharger will minimize unscheduled downtime and reduce the chance for potential damage to other engine parts. Turbocharger components require precision clearances and balancing due to operation at high rotational (torsional) speeds. Severe Service Applications can accelerate component wear and may suggest the need to inspect the cartridge at more frequent intervals.Removal and Installation
Refer to the Service Manual or consult with your Caterpillar dealer for the turbocharger removal and installation procedure and for turbocharger specifications. Consult with your Caterpillar dealer for turbocharger repair or replacement options.Clean/Inspect/Check
1. Remove the exhaust outlet piping and air inlet piping from the turbocharger. Visually check for oil leaks.2. Turn the compressor wheel and turbine wheel by hand. The assembly should turn freely. Inspect the compressor wheel and turbine wheel for contact with the turbocharger housing. There should NOT be any visible signs of contact between the turbine or compressor wheel and the turbocharger housing. If there is any indication of contact between the a rotating wheel and the housing, the turbocharger should be reconditioned or replaced.3. 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, a turbocharger oil seal leak may be indicated.The leak may be the result of extended engine operation at low idle or an inlet air line restriction (plugged air filters), which causes the turbocharger to "slobber".4. Use a dial indicator in order to check the end clearance on the turbocharger shaft. Attach the dial indicator point to the end of the turbocharger shaft. Push and pull the other end of the shaft. Note the total dial indicator reading. If the measured end play is greater than the Service Manual specifications, repair or replace the turbocharger.