Date registered: Aug 2012
Vehicle: 74 450 SEL, 78 300D, 99 Ford 7.3 turbo
Location: Douglas, Arizona
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The most common failure of turbochargers is burning of the oil seal, leading to leakage of engine oil into the compressor side. This is usually caused by the turbocharger being shut down quickly when it is very hot. The lubricating oil cools the shaft as the heat travels through the shaft from the turbine end (red hot) to the compressor end, which is relatively cool. If the cooling effect of the oil is abruptly terminated, there is sufficient heat in the shaft to burn the oil in the bearing, as well as cook the oil seal. For instance, Caterpillar mandates a 3-minute idle period prior to shutoff of large engines to allow cooling down of turbocharger shaft. I have a neighbor who fried 2 turbos on a Cummins engine in a Dodge truck by coming off the interstate, and immediately shutting the engine down. He is now a believer.