Cometic PRO3012T MLX Cylinder Head Gasket - .047 inch Bore 4.130 inch | 2011-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LML

Features:

• Fits 2011–2016 Duramax LML 6.6L engines
• Compatible with Silverado and Sierra HD models
• .047 inch compressed thickness for precise sealing
• 4.130 inch bore designed for LML applications
• Multi-layer steel construction for extreme durability
• Seals high-pressure and high-temperature environments
• Armor-clad and graphite reinforced materials
• Ideal for performance and heavy-duty use
• Conforms to irregular head and block surfaces
• Helps prevent head gasket failures and blowouts
• Designed for tight tolerances and long-term sealing

Protect Your Power With A Gasket That Refuses To Quit

When you’re pushing your LML Duramax to perform, you can’t afford to leave sealing to chance. The Cometic PRO3012T MLX Cylinder Head Gasket is purpose-built to handle the extreme demands of diesel power, whether you’re daily driving, towing heavy, or dialing up the boost. With a .047 inch compressed thickness and a 4.130 inch bore, it’s dialed in specifically for 2011–2016 GM Silverado and Sierra 2500HD and 3500HD trucks running the 6.6L Duramax. The result is a head gasket that holds tight under pressure, sealing combustion, coolant, and oil with confidence. Thanks to a blend of reinforced materials like armor-clad, graphite, and galvanized steel, this gasket does more than just get the job done, it does it without flinching. If you're in the middle of a top-end rebuild or serious performance upgrade, this is the part that lets you bolt things back together knowing you're good to go. It’s strength where it counts and peace of mind every time you turn the key.

Engineered To Handle Pressure Heat And Irregular Surfaces

The Cometic PRO3012T MLX Cylinder Head Gasket uses a multi-layer steel (MLS) design to deliver a premium sealing solution for high-compression diesel applications. Developed for 2011–2016 6.6L Duramax LML engines, this gasket features a 4.130 inch bore and a .047 inch compressed thickness for precise cylinder sealing. Its layered construction integrates advanced materials like armor-clad steel, graphite, and galvanized steel, which work together to conform to surface imperfections on cylinder heads and engine blocks. This is especially critical in diesel engines where block expansion, high heat, and combustion pressure push gaskets to their limits. The result is a high-integrity seal that resists blowouts, pressure leaks, and premature failure over time. It’s an excellent fit for stock replacement or high-performance builds, offering reliability and repeatability in demanding conditions. Whether you're assembling a refreshed top end or pushing higher horsepower, this gasket is built to perform with OEM fitment and aftermarket durability in mind.

Fits: 2011, 2012, 2013, 2014, 2015, 2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LML

Notes:

• Designed specifically for 2011–2016 6.6L Duramax LML engines.
• Fits Chevy Silverado and GMC Sierra 2500HD/3500HD models.
• Features a 4.130 inch bore and .047 inch compressed thickness.
• Constructed using Multi-Layer Steel (MLS) technology for maximum sealing performance.
• Reinforced with armor-clad, graphite, and galvanized steel materials.
• Engineered to handle extreme combustion pressure and high temperatures.
• Ideal for stock rebuilds or performance-based applications.
• Helps seal uneven or irregular mating surfaces for better long-term durability.
• No specific orientation required for installation.
• Recommended for professional installation to ensure proper fitment and torque specs.