My logan car has a faulty turbocharger when i was go to repair engine that time engine sound was a smooth but when mecanic replace turbocharger with fitting chines turbo cor then after few km engine run with abnormal sound . Mecanic then remove oil span he saw no3 big end bearing worn out why these happen please give me a factory manual of logan dls1.5
Turbocharger bearings are very sensitive to poor lubrication. Engine journal bearings are similar in that they are journal bearings, but they are much more robust in that there is splash oiling, in addition to pumped oil.
Given your description, I would expect that the car was run on low oil which caused lubrication starvation of the turbo. Usually that failure is very evident, and because it may mess up the mixture and fueling, it gets attention right away.
The number three crank bearing is a little more robust and will still function even after gross lubrication starvation. One reason for this is that the bearing does not have the rotational speed that the turbocharger bearing has.
My most likely estimate of what happened is that the engine had oil starvation, probably on several occurences. This frequently happens when the engine burns or leaks a little oil, and due to inattention, and then operation with low oil.
Dirty oil over a long time could also cause similar symptoms, however most frequently failures of the turbo and the main bearings is associated with under-lubrication or operation for a period of time with no lubrication.