Product Description
When it’s time to put your 2011-2016 LML 6.6L Duramax back on top, the FLEECE FPE-61-10004-D Factory LML Duramax Cylinder Head (Driver Side) delivers OEM-level reliability with Freedom Series performance. Built in Fleece’s state-of-the-art Freedom Racing Engine shop, this brand-new casting is inspected, pressure and leak tested, and equipped with all-new components so you can bolt it on and get back to towing, working, or daily driving with confidence.
Key Features & Benefits
- New casting – not a tired core, for long-term durability.
- All-new valve guides, springs, and valve seals for fresh top-end control.
- Pressure and leak tested to ensure sealing integrity before it ever leaves the shop.
- Precision ground stock valves with a 45-degree seat angle for excellent airflow.
- Multi-angle valve job for improved sealing and efficiency.
- No core charge – keep your old head or scrap it; no return hassle.
- Built for real trucks – ideal for daily drivers and heavy tow rigs that demand reliability.
Recommended Gaskets & Installation Notes
- Designed for use with OEM style head gaskets.
- Fleece recommends GM 12637788 (Grade C, Right) and GM 12637785 (Grade C, Left) head gaskets on LML applications.
- We highly recommend high-quality head studs or new OEM head bolts for any top-end refresh.
- Have the block deck checked for flatness before installation for best sealing results.
Vehicle Fitment
This cylinder head is engineered specifically for the driver side of 6.6L LML Duramax applications:
- 2011 Chevrolet Silverado 2500HD / 3500HD 6.6L LML Duramax
- 2012 Chevrolet Silverado 2500HD / 3500HD 6.6L LML Duramax
- 2013 Chevrolet Silverado 2500HD / 3500HD 6.6L LML Duramax
- 2014 Chevrolet Silverado 2500HD / 3500HD 6.6L LML Duramax
- 2015 Chevrolet Silverado 2500HD / 3500HD 6.6L LML Duramax
- 2016 Chevrolet Silverado 2500HD / 3500HD 6.6L LML Duramax
- 2011 GMC Sierra 2500HD / 3500HD 6.6L LML Duramax
- 2012 GMC Sierra 2500HD / 3500HD 6.6L LML Duramax
- 2013 GMC Sierra 2500HD / 3500HD 6.6L LML Duramax
- 2014 GMC Sierra 2500HD / 3500HD 6.6L LML Duramax
- 2015 GMC Sierra 2500HD / 3500HD 6.6L LML Duramax
- 2016 GMC Sierra 2500HD / 3500HD 6.6L LML Duramax
OEM Interchange / Cross Reference (OE Casting Numbers)
This Fleece head is designed to replace the following OEM part numbers (driver side LML):
- GM 12623949
- GM 12646217
- GM 12670434
- GM 12690607
Cross-Reference & Related Fleece Products (CPP Diesel)
Complete your Duramax top-end or browse other Freedom Series options with these Fleece cylinder heads on cppdiesel.com:
- FLEECE FPE-61-10004-P 2011-2016 FACTORY LML DURAMAX CYLINDER HEAD (PASSENGER SIDE) – matching passenger side head for a full LML top-end refresh.
- FLEECE FPE-61-10003-D 2006-2010 FACTORY LBZ/LMM DURAMAX CYLINDER HEAD (DRIVER SIDE) – for earlier LBZ/LMM 6.6L Duramax platforms.
- FLEECE FPE-61-10014-D FREEDOM SERIES DURAMAX CYLINDER HEAD FOR 17-23 L5P (DRIVER SIDE) – Freedom Series head for late-model L5P trucks.
- FLEECE FPE-61-10005 5.9L FREEDOM SERIES CUMMINS CYLINDER HEAD STREET – for 5.9L Cummins builds where you want the same Freedom Series quality.
Why Choose Fleece Freedom Series for Your LML?
Fleece has built a reputation for race-proven engineering and daily-driver reliability. Their Freedom Series cylinder heads bring that same attention to detail to your LML Duramax, giving you a ready-to-run, zero-core-charge solution that meets or exceeds OEM specifications. Whether you’re rebuilding after a failure or planning preventative maintenance, this head is built to handle towing, work use, and mild performance upgrades.
Specifications for FLEECE FPE-61-10004-D
| Specification | Value |
|---|---|
| Brand | Fleece Performance Engineering |
| Part Number | FPE-61-10004-D |
| Engine | 6.6L LML Duramax (2011-2016) – Driver Side |
| UPC | 670875716667 |
| GTIN | 670875716667 |
| Shipping Weight | Approx. 45 lb |
| Shipping Dimensions (W x H x D) | 15.00 in x 12.00 in x 23.00 in |
| Shipping Method | Ground – Free Shipping (continental U.S.) |
| Core Charge | None – no core charge required |
| OE Cross Reference | 12623949, 12646217, 12670434, 12690607 (driver side LML cylinder head) |
| E-Codes | Not specified |
| Prop 65 Warning | WARNING: Cancer and Reproductive Harm – www.P65Warnings.ca.gov |
Frequently Asked Questions
Is the FLEECE FPE-61-10004-D a new or remanufactured cylinder head?
This LML Duramax head uses a new casting that is fully machined, inspected, and assembled by Fleece in their Freedom Racing Engine shop. It is not a high-mileage core; you get a fresh cylinder head ready for installation.
What components come pre-installed on this cylinder head?
Each head includes new valve guides, springs, and valve seals. Valves are stock-style but precision ground with a 45-degree angle, and the seat area receives a multi-angle valve job for optimal sealing and airflow.
Do I need to send in my old head as a core?
No. This part is sold with no core charge, so there is no need to ship your old cylinder head back. That saves you both time and freight cost during the repair.
Does this cylinder head fit any other Duramax engines besides the 2011-2016 LML?
No. The FPE-61-10004-D is engineered specifically for 2011-2016 LML 6.6L Duramax applications on the driver side. For other generations like LBZ/LMM or L5P, refer to Fleece part numbers FPE-61-10003-D (LBZ/LMM) or FPE-61-10014-D (L5P), which are also available at CPP Diesel.
What else should I replace while I’m installing this cylinder head?
At a minimum, we recommend new OEM or performance head gaskets, fresh head bolts or head studs, and a complete top-end gasket set. It’s also a great time to inspect injectors, glow plugs, pushrods, and rocker arms for wear so you don’t have to reopen the engine later.
Is any custom tuning required after installing this head?
No tuning is required for a stock replacement installation. If you pair this head with larger injectors, turbo upgrades, or other performance modifications, proper custom tuning is recommended to maintain reliability and performance.
