New Chevrolet Duramax 6.6L GM L5P Silverado Sierra 2500HD 3500HD Cylinder Head

New GM GMC 6.6 OHV Duramax Diesel L5P Cylinder Heads (2017 and up) – Fully Loaded

Duramax 6.6L GM L5P Silverado Sierra Cylinder Heads

Experience unmatched performance with our New GM GMC 6.6 OHV Duramax Diesel L5P Cylinder Head, expertly designed for 2017 and newer models. This premium cylinder head comes fully equipped to meet the rigorous demands of your vehicle.

Features:

• Precision Engineering: Meticulously crafted for peak performance and reliability.
• Quality Assurance: Each cylinder head undergoes rigorous cleaning, inspection, and pressure testing.
• Ready for Installation: Includes quality valve seals and is vacuum tested to ensure a perfect seal.
• Core Return Required

Benefits:

• Enhanced Durability: Built to endure tough conditions, extending your engine’s lifespan.
• Improved Performance: Optimizes engine efficiency and enhances power output.
• Perfect Fit: Engineered specifically for GMC models from 2017 onwards, ensuring seamless compatibility.

Fits:

Heavy Duty Parts Company – Core Returns Policy

Effective December 17, 2025

At Heavy Duty Parts Company, core returns are essential to our ability to provide high-quality, cost-effective cylinder heads. Returned cores supply critical components—such as keepers, springs, and retainers—that are vital to proper engine performance and allow us to maintain OEM-level quality.

No Upfront Core Charge

Unlike many suppliers, we do not charge a core fee upfront. Instead, we rely on customers to return their used cores within the required timeframe.

Core Return Requirements

• Cores are due within 30 days of the purchase date

• If a core is not returned within 60 days, the product warranty is void

• Unreturned cores will be charged as follows:

  • Cylinder heads under $600: $200 per unreturned core

  • Cylinder heads $600 and above: $400 per unreturned core

Customers needing additional time may contact us to request an extension. Approved extensions will prevent core charges from being applied.

Core Return Process

Cylinder heads are shipped with prepaid core return labels included in packets attached to the outside of each box. If labels are missing, customers should contact us for replacements prior to returning the core.

Core Eligibility

Some cylinder heads do not require a core return. In certain cases, core requirements may be waived at our discretion.

Why Core Returns Matter

• Reused core components help maintain OEM-quality standards

• Core returns allow us to keep pricing competitive

• Recycling cores supports sustainability by reducing waste and conserving resources

This policy applies to all purchases made on or after December 17, 2025.

Send Back All Components

To ensure the quality and integrity of our remanufacturing process, we ask that you return all components that were originally included with your new cylinder head. This includes items such as:

• Rocker arms
• Camshafts (if applicable)
• Any other hardware that came with your purchase

Easy & Free Core Return Process

• Each purchase includes a prepaid core return label in a plastic sleeve on the box.
• Simply pack your core with all included components, attach the label, and drop it off with the carrier—no extra cost to you.
• Returned cores undergo inspection and recycling, ensuring maximum efficiency.

Customer Partnership & Sustainability

By returning your core and its components, you help maintain a reliable supply chain, ensuring we can continue offering top-quality products at the best prices. This process not only benefits your wallet but also contributes to a greener and more efficient automotive industry.

We appreciate your support in keeping our business and the industry running smoothly!

Warranty and Support:

• Enjoy peace of mind with a 2-year unlimited mileage warranty.
• Expert support is available at sales@heavydutypartscompany.com

Why Choose Heavy Duty Parts Company?: At Heavy Duty Parts Company, we are dedicated to excellence and customer satisfaction. Our L5P Duramax engines undergo extensive testing to exceed industry standards for reliability and performance.

Learn About Diesel Fuel Injectors

CHECK OUT OUR OTHER DIESEL CYLINDER HEADS HERE

LEARN ABOUT THE L5P ENGINE: HERE

Duramax 6.6L GM L5P Silverado Sierra Cylinder Heads