Does pleural effusion from ascities resolve by itself without treatment ?

Depends on: The cause , if some one develops plural effusion after an attack of pancreatic inflammation , when it subsides effusion will clear , or some thing like advanced malignancy will not clear speak to your doctor

Usually not: It can, but typically if you have ascites bad enough to have a pleural effusion, it's from severe liver disease and it will not go away. You control the pleural effusion usually by controlling the ascites.