No moving parts in an intercooler. It's just a RADIATOR. The wailing comes from a moving part. Get a LONG handled screwdriver, hold the tip to moving parts and hold the other end to your head next to your ear. Bone conduction will do the rest. It acts as a stethoscope.
Of it is poorly accelerating, check any rubber connections post turbo. The wailing may be a hole it rip in a rubber boot... Turbo whine and air escaping?
Otherwise I would concentrate on your turbo 1st.
Does it make the noise when it's stopped? What about revved up when stopped? Where does it sound like it's coming from, towards the front, rear, left right? Need a lot more info on whats going on.