Purchased c4500 with lb7 start right up, seller said would shut off anywere from 10 min. To 30 min. Disconnect fuel lines put in jar ran concentrate injected cleaner molly though it . Never shut down ran hr. Was surging and lot of soot around intake from back side. Tried pressure test through front turbo inlet. Air leaking out right side exhaust , none on left. Do I need to turn motor to close valves on right and test again. With a scope I found soot between turbo/leaking between hot and cold sides , rebuilt turbo. Any help before I reassemble