2 YEAR UNLIMITED MILEAGE WARRANTY ON ALL AUTOMOTIVE CYLINDER HEADS

727-609-1700

sales@heavydutypartscompany.com

727-609-1700 | Email Us

6.6 duramax pair

Recommended buying from here, it was really quick and easy

Howard T, Minnesota

New Complete Pair GM GMC Chevrolet 6.6L OHV Duramax Diesel LML Cylinder Heads 2011-2016

$1,500.00

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Pay with Credit Card

Additional Info

Brand New · Not Remanufactured · In Stock
Complete Pair — 6.6L LML Duramax
Cylinder Heads · 2011–2016

These are brand-new high-density iron castings — not rebuilt cores of unknown history. Every pair is precision-machined in-house on Rottler equipment, pressure tested to 60 PSI, vacuum tested port-by-port, and assembled in a clean environment before it ships. The result is a drop-in replacement engineered to handle the LML’s demanding cylinder pressures and thermal loads right out of the box.

🛡️ 2-Year Unlimited Mileage Warranty
🔬 Pressure Tested to 60 PSI
🏭 In-House Precision Machined
📦 Ships UPS Ground — Lower 48
↩️ No Upfront Core Fee

Technical Specifications

Engine Displacement 6.6L Duramax Diesel
Engine Code LML
Valve Train OHV (Overhead Valve)
Condition ✓ Brand New — Not Remanufactured
Year Range 2011 · 2012 · 2013 · 2014 · 2015 · 2016
Quantity Complete Pair — Driver & Passenger
Included Valves & Springs Pre-Installed
Gasket Surface Pre-milled & MLS gasket verified
Pressure Test 60 PSI — Exceeds Factory Standard
Warranty 2-Year Unlimited Mileage
Shipping UPS Ground — Lower 48 States

Our In-House Machining Process

Every head runs through our full in-house process — not just pulled off a shelf and shipped.

Step 01
Chemical Clean & Debris Removal

Every casting is chemically cleaned and blown out — removing oils, shavings, and debris so your oiling system stays uncontaminated from first start.

Step 02
Guide Sizing & Valve Seat Cutting

Final guide sizing and precision multi-angle valve seat cutting on Rottler equipment — perfect geometry and clearances before anything goes to the assembly bench.

Step 03
Pressure Tested to 60 PSI

We go beyond the factory standard. Every head is verified at 60 PSI to confirm zero porosity leaks or internal defects that could compromise cooling or oiling.

Step 04
Dimensional Inspection

Multi-point gasket surface and bore alignment inspection. Perfectly flat within OEM tolerances — critical for a proper MLS head gasket seal.

Step 05
Clean-Room Assembly

Valvetrain components installed in a controlled environment. Spring heights and seal seating verified — balanced and ready for high-performance use.

Step 06
Vacuum Seal Verification

Every intake and exhaust port is vacuum tested for a 100% airtight valve-to-seat seal — maximum compression and peak performance from day one.

Vehicle Fitment

Fits all 2011–2016 GM trucks and vans equipped with the 6.6L Turbo Diesel LML engine code.

Chevy Silverado 2500 HD
2011–2016 · 6.6L LML
Chevy Silverado 3500 HD
2011–2016 · 6.6L LML
GMC Sierra 2500 HD
2011–2016 · 6.6L LML
GMC Sierra 3500 HD
2011–2016 · 6.6L LML
GMC Sierra Denali 2500
2011–2016 · 6.6L LML
GMC Sierra Denali 3500
2011–2016 · 6.6L LML
Chevy Express 2500 Van
2011–2016 · 6.6L LML
Chevy Express 3500 Van
2011–2016 · 6.6L LML
GMC Savana 2500 Van
2011–2016 · 6.6L LML
GMC Savana 3500 Van
2011–2016 · 6.6L LML

▼  Full Year-by-Year Fitment List
10 Models · 60 Fitments
Vehicle
Model Years
Chevrolet Silverado 2500 HD
6.6L Turbo Diesel LML
201120122013201420152016
Chevrolet Silverado 3500 HD
6.6L Turbo Diesel LML
201120122013201420152016
GMC Sierra 2500 HD
6.6L Turbo Diesel LML
201120122013201420152016
GMC Sierra 3500 HD
6.6L Turbo Diesel LML
201120122013201420152016
GMC Sierra Denali 2500
6.6L Turbo Diesel LML
201120122013201420152016
GMC Sierra Denali 3500
6.6L Turbo Diesel LML
201120122013201420152016
Chevrolet Express 2500 Van
6.6L Turbo Diesel LML
201120122013201420152016
Chevrolet Express 3500 Van
6.6L Turbo Diesel LML
201120122013201420152016
GMC Savana 2500 Van
6.6L Turbo Diesel LML
201120122013201420152016
GMC Savana 3500 Van
6.6L Turbo Diesel LML
201120122013201420152016
All vehicles require 6.6L Turbo Diesel · LML engine code  ·  Not sure? Call 727-609-1700

Warranty & Core Return

🛡️ 2-Year Unlimited Mileage

No mileage caps. No fine-print traps. If a covered defect arises, we make it right — period.

View Full Warranty →

↩️ No Upfront Core Charge

Receive your heads, install them, then use the pre-paid return label included in your shipment. Cores due back within 30 days.

View Core Policy →

Why Heavy Duty Parts Company?

The LML Duramax demands precision. A sloppy head job means repeat gasket failures, coolant in the combustion chamber, and oil contamination. Our heads are brand-new castings machined in-house, tested to 60 PSI, and verified before they leave the building. This isn’t shelf stock — it’s a part we’d put on our own truck.

Fits 2011–2016 Chevy Silverado 2500HD & 3500HD, GMC Sierra 2500HD & 3500HD, Sierra Denali 2500 & 3500, Chevy Express 2500 & 3500 vans, and GMC Savana 2500 & 3500 vans — all with the 6.6L LML engine.

Mon–Fri · 8AM–5PM Eastern · We Know Duramax

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★★★★★

“These guys know their stuff when it comes to cummins, they knew what head number I needed and gave me a quote on the spot”

Raymond Adelante, Florida

★★★★★

“They were nice to talk to on the phone and were easy to deal with, especially since I’ve never ordered something like this before! Thank you”

Jenifer Longarden, Ohio

★★★★★

“Local shop recommended buying from here, it was really quick and easy”

Howard Trent, Minnesota

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