Hello together, Can wrong or thin oil 0W50 before 10W40 Mobile! behind outpuff blue smoke cause? Qualty at empty run barely visible but stinks after verbrantes oil! When giving gas(Not always) squalors medium strong clearly blue clouds! Motor after 30km driving around 90% city so operating temp.already reached ander ampel od.wagen sometimes stands blue clouds short time 1-3 sec.very visible.naturally the oil smell always there! my friend meant he had put in when changing oil 0W50 allegedly for Diesel engines were suitable, but should be changed shortly again! We had suspected the VSD was defective but he changed the same engine last week because of squalm VSD but without success motor squalmt continued he probably said piston rings….. that’s why I wanted to go safe instead of that and change then squalmt further etc. Jetz ask you Can really cause thin oil squalms??For your help I am very grateful!!!