Exhaust manifold lock nut. Left.DIESEL. Right.DIESEL. A solid metal or plastic bLock with a threaded hole in the center which is used to tighten or adjust the Exhaust Manifold Heat Shield. A solid metal or plastic bLock with a threaded hole in the center which is used to tighten or adjust the Fuel Evaporative Emission Control System Line. A solid metal or plastic bLock with a threaded hole in the center which is used to tighten or adjust the Intercooler pipe. A solid metal or plastic bLock with a threaded hole in the center which is used to tighten or adjust the Turbocharger Heat Shield. Catalytic Converter Nut. Exhaust Gas Recirculation (EGR) Tube Nut. Exhaust Manifold Nut. Part cannot be reused/reinstalled. Part is not reusable. replace only. Turbocharger Nut.