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An Dongfeng EQ1141G car, which is equipped with Cummings 6BT engine, has been running 10 thousand kilometers. In the use of the engine, the engine suddenly has "flying car", accompanied by abnormal noise and a large number of blue smoke in the exhaust pipe. Fault detection: according to the fault phenomenon, first check the high-pressure oil pump, check the oil quantity adjustment gear lever and speed governor, all movement is flexible, no stuck and loose phenomenon. Then the high pressure oil pump is adjusted, but the fuel supply in oil at various engine speeds is fast and the oil supply is fast, and the oil supply of each cylinder meets the requirements. Finally, a thorough inspection of the engine revealed that there was a small amount of oil flowing out of the exhaust turbocharger. The exhaust turbocharger was removed and the impeller was seriously damaged and the turbine shaft was broken. Check the intake system. There is a lot of oil coming into the cylinder. Troubleshooting: remove the residual oil in the intake system, replace the exhaust turbocharger assembly and the engine oil of the Cummins engine, restart the test, and the engine work is restored to normal. Fault analysis: because of the high speed operation of the exhaust turbocharger, the radial clearance and the axial gap are too large after the sudden break of the turbine shaft, which aggravate the wear of the bearing, cause the seal ring unsealed, the oil leakage of the turbocharger, the deformation of the impeller and so on, and then cause the engine to supply the engine oil of the waste gas turbocharger with the air. The compressor is sent to the combustion chamber, causing the engine to "fly" and the exhaust pipe to discharge a large amount of blue smoke.