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Diesel engine exhaust became bluish and oil consumption increased. What could cause this? Is it Turbo which losing the oil?

04 Aug '18, 07:03

Aug. 4, 2018, 7:03 a.m.
KnowledgeBase's gravatar image


The simultaneous increase of oil consumption and blue smoke could be because of the turbocharger losing the engine oil through the intake or exhaust duct. The cause of last can be a clogged, bent or coked drain line. This is possible due to defective labyrinth sealing, too high oil level or too high internal pressure in the crankcase as well.
Unlike other engine components, the turbochargers do not have elastomeric radial sealing rings for the shaft. The reason for this is the high temperature and the speed of rotation, reaching 330,000 rpm.
Both behind the turbine wheel and behind the compressor wheel there is a labyrinth seal that prevents the engine oil from escaping and the penetration of compressed air and hot exhaust gases into the bearing housing. The corresponding gas pressure from the turbine and compressor wheel side prevents the engine oil from escaping. Disks located on the shaft of the turbocharger operates in such a way that the engine oil escaping from the bearing installation places is thrown away from the turbocharger shaft by centrifugal force.
The engine oil emitted from the radial bearings, as well as the intake air and the exhaust gases entering the turbocharger, are led back through the drain pipe to the oil pan.
If the turbocharger loses engine oil through the intake or exhaust duct, the balance of pressure is usually broken due to problems with the oil/gas recirculation line:
* clogged, bent, tapered or coked drain line
* too high oil level
* too high internal pressure in the crankcase due to excessive wear of the pistons, piston rings and cylinder openings (too many crankcase gases)
* too high internal pressure in the crankcase due to inoperative crankcase ventilation

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04 Aug '18, 07:13

Aug. 4, 2018, 7:13 a.m.
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