If you take a plug of the correct size- the inside diameter of the turbo hose- and install a schrader valve you can use compressed air to check for leaks in the system.

I use a master cylinder cap with a schrader to bleed my brakes using a bicycle pump. Turns out the cap is the correct size for the turbo outlet hose. I use a hose clamp around the outlet hose and turn my regulator on my air compresser down to 15psi. I use that to pressurize the system and the leaks are then apparent. I find leaks I miss with visual inspection. Good luck.

Randy