Fleece Performance FPE-DMAX-CBOP Duramax Billet Coolant Block-Off Plate

Stop rear coolant leaks for good. The factory rear engine coolant cover on GM 6.6L Duramax engines is a well-known failure point. Over time the gasket dries out and the cast housing corrodes, leading to persistent coolant leaks at the back of the engine.

The Fleece Performance FPE-DMAX-CBOP Billet Coolant Block-Off Plate is the premium, permanent solution. CNC-machined from high-quality billet aluminum, this direct-fit upgrade is significantly thicker and stronger than the OEM cover. It features an integrated square-cut O-ring seal, eliminating the need for a separate gasket and delivering a reliable, leak-free seal that lasts.

Key Features

• Billet aluminum construction — superior strength and corrosion resistance compared to factory cast parts
• Thicker than OEM — added durability for long-term reliability
• Integral square-cut O-ring — no gasket required for a cleaner, more secure seal
• Direct replacement for GM part numbers 97941204 and 12698239
• Includes necessary mounting hardware for straightforward bolt-on installation
• Black anodized finish for a clean, professional appearance and extra protection
• Made in the USA by Fleece Performance Engineering

Vehicle Fitment

2001–2025 GM 6.6L Duramax (LB7, LLY, LBZ, LMM, LML, L5P)

• Chevrolet Silverado 2500HD / 3500HD
• GMC Sierra 2500HD / 3500HD

This is one of the most popular and effective upgrades for Duramax owners looking to eliminate a common leak source and add peace of mind. Whether you're fixing an existing leak or preventing one proactively, the Fleece billet block-off plate is a smart, reliable choice.