New Complete Pair GM GMC 6.6L OHV Duramax Diesel LML Cylinder Heads 2011-2016 W/ Head Gasket Set & Bolts

Upgrade your Duramax engine with these brand new GM GMC 6.6 OHV LML cylinder heads, designed to fit 2011–2016 models. Built to meet or exceed OEM specifications, these fully loaded heads come ready for installation with valves, springs, and seals already assembled.

These cylinder heads are perfect for anyone looking to replace worn or damaged heads in their truck or commercial vehicle. The heads are pressure tested to ensure optimal performance and reliability, offering a seamless fit for your LML Duramax engine. Whether you’re upgrading for better performance or simply need a replacement, these loaded cylinder heads are engineered for durability and efficiency. A core return is required for this purchase.

Features:

• Fits 2011–2016 GM GMC Duramax 6.6 OHV LML Diesel engines
• Comes fully assembled with valves, springs, and seals
• Precision-machined and pressure tested for performance and reliability
• Direct replacement with a perfect fit for easy installation
• Designed to meet or exceed OEM specifications

6.6 OHV Duramax Cylinder Heads Applications:

• 2011–2016 GM and GMC trucks with Duramax 6.6 LML Diesel engines
• Compatible with various heavy-duty applications, including commercial trucks and pickups

Why Choose These Cylinder Heads? These loaded cylinder heads are perfect for those looking to restore or upgrade their 6.6 Duramax LML engine. With high-quality construction and a direct fit, they provide enhanced durability and performance for your truck or commercial vehicle. Whether you use your vehicle for towing, hauling, or daily driving, these cylinder heads are built to last.

GM GMC 6.6 OHV Duramax Diesel LML Cylinder Heads Specifications:

• Engine: Duramax 6.6 OHV LML Diesel
• Year Range: 2011–2016
• Fully loaded: Includes valves, springs, and seals

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!

Order GM GMC 6.6 OHV Duramax Diesel LML Cylinder Heads Today!

Order Now for Fast Shipping! Get your truck back on the road with these brand new, fully loaded Duramax LML cylinder heads. We ship to the lower 48 states, ensuring you receive your parts quickly and hassle-free. Upgrade your engine today!

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