New Pair Duramax 6.6L GM Silverado Sierra Cylinder Heads Loaded LMM



New Duramax 6.6L GM LMM

Original price was: $1,400.00.Current price is: $1,250.00.

In Stock


Duramax 6.6L GM LMM Silverado Sierra Cylinder Heads



8th digit of vin = 6


FITS: 2011-2016 Chevy Silverado 1500, 2500, GMC Sierra Trucks

For more information on the L5P engine check this out:

Are if you want so check out some of our other Duramax diesel heads for sale here:

A cylinder head is an essential component of an internal combustion engine. It sits atop the engine block and forms the top of the combustion chamber. It contains the intake and exhaust valves, spark plugs, and fuel injectors, all of which play critical roles in the engine’s operation. During the engine’s operation, the cylinder head seals the top of the combustion chamber to contain the extreme pressures and temperatures generated during the combustion process. The intake valves allow the air-fuel mixture to enter the combustion chamber, while the exhaust valves allow the burned gases to exit. The spark plugs ignite the air-fuel mixture, initiating the combustion process. The fuel injectors ensure that the correct amount of fuel is delivered to the combustion chamber. Overall, the cylinder head is responsible for controlling the flow of air and fuel into the combustion chamber and the evacuation of exhaust gases, ultimately contributing to the engine’s performance and efficiency.

SHIPPING: Shipping is a flat rate in the lower 48 states. If shipping elsewhere please give us a call for freight options. 727-572-1958



Clearwater Cylinder Head, Inc. thoroughly cleans, inspects, and pressure tests all our cylinder heads. All seat and guide work is performed as needed on the latest state-of-the-art Serdi or Sunnen seat and guide machine. The head then moves on to a Rottler CBN resurfacing machine where it is cut to the required RMA finish. We then install a quality valve seal and pull a vacuum on each valve to ensure there is a perfect seal between the valve and the seat. All machine work is performed on the latest state-of-the-art equipment. Head is complete and ready for installation.

Hours of Operation: Monday – Friday 8 AM to 5 PM EST


WARRANTY INFORMATION: Clearwater Cylinder Head, Inc. provides a TWO(2) year unlimited mileage warranty. A copy of the warranty card will be enclosed with your invoice.
Clearwater Cylinder Head, Inc.
5100 Ulmerton Road #2
Clearwater, FL 33760 USA
Clearwater Cylinder Head, Inc. is dedicated to quality craftsmanship and is pleased to offer this warranty. We invite you to read this entire document carefully prior to installing your cylinder head.
Please do not hesitate to contact us should you have any questions.

All New Duramax 6.6L GM LMM Silverado Sierra Cylinder Heads Loaded with Valve and Springs are machined, assembled and built in house in our Florida facility.

Duramax 6.6L GM LMM Silverado Sierra Cylinder Heads

How to Know If You Need a New Cylinder Head?

Every engine is due for repairs from time to time. Among the most important pieces of most engines is the cylinder head, which, if damaged, can prove increasingly perilous the longer it goes unrepaired. Here are some warning signs and symptoms which may be caused by cylinder head damage.

Weak Engine

Cylinder heads are responsible for containing and directing the internal combustion of an engine’s cylinders, meaning if that ability is hindered, the engine’s efficiency and power may take a hit. This can be seen in lower gas mileage, sluggish acceleration, and difficulty getting up steep inclines.

The Verdict: This is most often among the first signs of a cracked cylinder head, and usually can be repaired if caught in its early stage.

Oil Leakage

Oil is responsible for lubricating the engine’s mechanical parts, including the cylinder head. A cracked cylinder head can cause this to leak, which can be most noticed by a puddle of oil forming on the ground when the vehicle is parked for a long enough time. Such a sign can be a cause for concern, as oil or coolant may also back up into the engine’s internal chambers if the crack is large enough.

The Verdict: Usually, unless oil has backed up into the engine and caused any damage to other parts, a leaking cylinder head can still be repaired and may not require replacement.

Magnaflux Test Cylinder Heads - Clearwater Cylinder HeadCoolant Leakage

Coolant is responsible for cooling the engine, cylinder head, and many other processes. Similarly to oil, a cracked cylinder head can cause coolant to leak. This can be noticed by either a puddle forming beneath the car when parked or an overheating warning lighting up on the vehicle’s dashboard. Coolant can potentially contaminate the oil, and therefore the cylinder head should be repaired as soon as possible.

The Verdict: Unless the coolant has contaminated the oil due to a large enough crack in the cylinder head, at this stage the head can usually be repaired, not replaced.

Engine Misfires

Within an engine’s cylinders, air and gas form a pressurized mixture which explodes upon ignition, creating power. A cracked cylinder head may be unable to create the required atmosphere for proper combustion within those cylinders, leading to failures to combust, or engine misfires. The engine may die repeatedly during use, or fail to start at all.

The Verdict: This is a more severe sign, and usually is indicative of serious damage. It’s always better to take a cylinder head in for repairs or replacement if it starts to show signs of wear, to avoid even higher repair bills when the cylinder head’s failure leads to damages elsewhere in the vehicle.


White smoke coming from the engine can indicate a catastrophic failure of the cylinder head, in which exhaust gases are vented directly into the engine space. This is the last stage of total cylinder head failure, and should be avoided by simply going in for repairs at the first signs of damage.

The Verdict: A cylinder head at this stage must be replaced as soon as possible, as it’s either venting exhaust gases or causing coolant to contaminate the oil, neither of which are healthy for any vehicle’s systems.

The Cylinder Head Repair Experts

Since repairing bad cylinder heads or gaskets is not a typical DIY project, we recommend that you consult a professional company. Clearwater Cylinder Head Inc. (CCH) is a reputable, experienced (over 25 years) dealer. We specialize in providing quality and warranty-backed rebuilt cylinder heads for a variety of vehicles (cars, trucks, boats, etc). With a massive online catalog of cylinder heads, we most likely have the cylinder heads for your repair needs. The knowledgeable staff at CCH is happy to help you find the cylinder head that is right for your vehicle. Please contact Clearwater Cylinder Head Inc. toll-free at 1-800-572-1963.

The cylinder head is one of the most vital parts to your car’s mechanics; your gas-powered car could not work without it. The cylinder head and head gasket sit atop the engine block over the cylinders. The head covers and protects the engine components and creates the correct vacuum for the engine to work. The cylinder head works along with the camshaft, induction and exhaust systems to process the fuel, air, and exhaust to provide your car’s horsepower. Damage, such as, leaks or cracks, in your cylinder head can cause monumental damage to your engine. The correct shape, size, quality, and use of your cylinder head can make all the difference in how your car runs and can help avoid costly engine repairs. To choose the best cylinder head for your specific needs follow these tips for “5 Things to Check Before Buying a Cylinder Head” when choosing a rebuilt, remanufactured, or new cylinder head…

  1. Choose a Compatible Head – Only choose from cylinder heads designed for your car’s specific make, model, year, engine size, and engine enhancements (turbo, supercharger, etc.). Choose a cylinder head metal (aluminum or cast iron) that is compatible with what your engine block is made of as the metals contract and expand at different rates; mismatched cylinder heads are prone to cracking. Choose a cylinder head with right hardware (bolts) for the engine block to ensure your head will fit correctly.
  2. Consider Intake and Exhaust Port Volumes – Bigger intake port volumes are not always necessarily better; depending on engine size and/or application, smaller intake ports may be more suitable. Smaller intake ports often provide better performance for street application as they produce more low-end torque and crisper throttle response, while larger intake ports are more beneficial for larger or higher-revving engines as they allow for more air flow. Choose a good-flowing exhaust port that is the correct size, by comparing to stock exhaust port volume and valve size for your specific engine.
  3. Determine the Combustion Chamber Size and Design needed for Your Engine – Choose a combustion chamber size that raises the compression ratio to maximize your engines efficiency, while matching the components of your specific engine, such as, bore, stroke, head gasket, and piston shape, as well as, deck clearance and ring location.
  4. Consider Application – Whether you are using your car for street or off-road driving or drag, circle track, or road racing, deciding the primary application for your engine is important is picking out the cylinder head to best fit your needs. Valve lift, air flow, and duration can be altered to provide the best performance for your car’s specific application.
  5. Buy from a Reputable Dealer – Choose cylinder heads from a reputable dealer! Clearwater Cylinder Head Inc. (CCH) is dedicated to providing customers with quality cylinder heads backed by their warranty. The knowledgeable associates at CCH would be happy to help you in choosing the cylinder head that is right for your specific needs. Contact Clearwater Cylinder Head Inc. toll free at 1-800-572-1963 or by email at

The diesel engine, also known as the compression-ignition (CI) engine, is an internal combustion engine which can be found in a broad range of vehicles. It comes with the benefits of increased fuel efficiency and fewer mechanical problems, but at the risk of more expensive–though rarer–trips to both the gas station and the repair shop.


Rudolph Diesel grew up and studied steam engines at the turn of the century. At the time, steam power was king, but required so much coal and such expensive maintenance for so little output that only large companies could afford them. He began development in 1885, and by 1897 had produced a test engine with an efficiency 2.6x higher than many steam engines.

Sadly, his success was not immediate. While marketing his invention, he suffered a nervous breakdown and slowed development. Dogged by many other engineers, companies, the threatened coal industry, critics, and financial troubles, he went missing from a ship on a voyage to England in 1913 and was presumed dead.

Following his death, his patents began to expire, and a number of companies resumed development of the engine into what we see today.

How it Works

The most key difference between gasoline and diesel engines is how they ignite the fuel mixture inside their internal chambers. While gasoline engines use spark plugs to ignite fuel, diesel engines use mechanical compression to increase the temperature of the air inside their chambers enough that the fuel ignites spontaneously.

This means diesel engines tend to be of simpler, sturdier design, as they lack the electronics required for spark plugs to function, and must be built to withstand the high pressures of the compression-ignition process.

The cylinder head of a diesel engine follows these differences as well: instead of including spark plugs, a diesel cylinder head has injection nozzles, and may include glow plugs. Glow plugs shorten the engine’s starting time in very cold weather by briefly operating in a similar manner as spark plugs, until the engine warms enough to operate on its own.

In Conclusion

A major advantage of the diesel engine is its fuel efficiency. Out of all other combustion engines, diesel engines produce the highest level of energy for how much fuel is burned. There’s also a broad diversity of fuels it can accept, including fuel oils and biofuels. These fuels are less flammable, can have good lubrication properties, and in the case of biofuels, can even be made for free from discarded oils and other materials!

Some popular diesel cylinder heads on offer from Clearwater Cylinder Head:

  • Ford Powerstroke 6.0, 6.3, and 7.3
  • International Navistar 7.3 IDI
  • 5.9L 12V & 24V 6BT Cummins engine
  • Duramax 6.6L & 2.8L

Ultimately, diesel engines can be highly reliable and suit a broad range of uses, whether found in a luxury town car or a workhorse truck. Just as with gasoline engines, the deciding factor is the personal choice and needs of the buyer.

The Cylinder Head Repair Experts

Clearwater Cylinder Head Inc. (CCH) is a reputable, experienced (over 25 years) dealer. We specialize in providing quality and warranty-backed rebuilt cylinder heads for a variety of vehicles (cars, trucks, boats, etc). With a massive online catalog of cylinder heads, you can view CCH’s inventory of diesel cylinder heads. If you have a rare or hard to find cylinder head, we can rebuild that for you. The knowledgeable staff at CCH is happy to help you find the cylinder head that is right for your vehicle. Please contact Clearwater Cylinder Head Inc. toll-free at 1-800-572-1963.

For More information on diesels and diesel parts check this out: