The most common symptoms of a leaking turbo include a lack of power, random misfires, blue or black exhaust smoke, and peculiar noises. The blue and black exhaust smoke is the biggest indicator of an oil leak. Oil can come out of the Engine and get into the exhaust side of the Turbo. When the Turbo was off you should have been able to see inside of the exhaust manifold. If the inside of the exhaust manifold has that shiny wet looking carbon you have issue with your cylinder head or engine. 1 - 12 of 12 Posts. Here are the most common symptoms of an exhaust leak: Loud Rumbling Sound - As the exhaust leak escapes through holes in the exhaust, it will let out a deep rumble sound. This is the sound of unmuffled exhaust, and is the most obvious symptom of an exhaust leak. Smell - Leaking exhaust smells terrible. If your Tucson has leaking exhaust.