Case 650 Crawler Dozer Repair Manual

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Manual Extract: CAUSES OF PREMATURE TURBOCHARGER FAILURE

Certain operating and maintenance conditions can arise which could cause premature turbocharger failure. NOTE: The total solution to the problem is not in repairing the failure, but in determining the cause. Replacing a damaged turbocharger without determining the cause will frequently result in a repeat failure.

Lack of Lubricating Oil
This type of failure can occur when the amount of oil being supplied to the turbocharger is insufficient to lubricate or cool bearing and journal surfaces.
Operating temperatures affect the volume of oil required by the turbocharger. As turbocharger speed or engine load increases, the

need for lubricating oil increases. NOTE: Insufficient oil for periods as short as five seconds can cause failure. This is why it is necessary to prime the turbocharger as part of the everyday operating procedure. IMPORTANT: It is very important that adequate

lubrication reaches the turbocharger bearings and throughout the engine before operating the engine at rated speed.
High Exhaust Temperature

Excessive temperature in the exhaust system will cause lubricating oil to coke in the center housing drain annulus at the turbine end. Oil leakage, carbon deposits and eventual damage to the back of the turbine wheel will result.

High exhaust temperature can also erode the turbine housing creating pitting and deposits on the turbine wheel.
High exhaust temperature can be caused by the turbocharger itself. Carbon build up on the turbine wheel, if severe, will slow the rotating assembly, reducing the amount of inlet air.