Probable Causes
- Excess engine oil
- Failure of the turbocharger oil seal
- Worn valve guides
- Worn piston rings and/or worn cylinder walls
- Wear or damage to pistons
Recommended Repairs
Excess Engine Oil
Ensure that the engine crankcase contains the correct amount of engine oil. If the level of the engine oil increases during engine operation, fuel may be leaking into the oil. Check for fuel in the engine oil. Refer to Troubleshooting, "Fuel In Engine Oil".
Failure of the Turbocharger Oil Seal
If the oil seal in the turbocharger fails, oil will leak into the inlet manifold. Check the inlet manifold for oil. If oil is present, repair the turbocharger.
Worn Valve Guides
Inspect the valve guides for wear. Refer to the Specifications module for the maximum permissible wear of the valve guides. If necessary, recondition the cylinder head.
Worn Piston Rings and/or Worn Cylinder Walls
Piston rings that have excessive wear can cause too much pressure in the crankcase. The additional pressure in the crankcase will cause more than the normal amount of crankcase blowby from the crankcase breather. Use the 8T-2700 Blowby/Air Flow Indicator to check the amount of crankcase blowby. The test procedure is in Special Instruction, SEHS8712. Inspect piston rings and install new parts, as required.
Wear or Damage to Pistons
Inspect the piston for excess wear. Check the clearance between the piston rings and the grooves. Pistons which have worn grooves can cause blue smoke. Damaged pistons can cause blue smoke. Damaged pistons and worn grooves can also cause excessive oil consumption. Ensure that the oil return holes that are under the oil ring are open. Install new components, if necessary.