Eliminate coolant leaks from the rear housing on your Duramax engine with this billet aluminum block off plate from PPE. The rear housing on the Duramax engines are constructed of a thin plate and gasket that can corrode and the plate can warp causing a coolant leak over time. This block off plate from PPE is constructed of CNC machined billet aluminum and features a built in o-ring seal for a leak and warp free installation using the factory hardware.