Smeding Diesel Billet Coolant Block Off Plate for 6.6L Duramax 2001-2025

Eliminate rear engine coolant leaks permanently with our upgraded block-off plate!

Designed as a direct improvement over factory covers, our billet aluminum rear cover plate features a robust, thicker design and a built-in square-cut O-ring—no gasket needed. Unlike the original equipment, which can develop leaks as it ages, this precision-machined solution offers a long-lasting seal to keep your cooling system leak-free for the long haul.