Home » GM 6.6 L Duramax Engine Review

GM 6.6 L Duramax Engine Review

With a 6.6 L Duramax engine, GM has created the most powerful and efficient pickup truck ever to be sold in North America. With an incredible 8% better fuel economy than its nearest competitor, it’s no wonder that this engine is quickly becoming the choice for many drivers.

This engine was designed by General Motors specifically for use in heavy haulers like trucks, buses, and construction equipment. If you are looking to buy a truck or other vehicle equipped with this powerhouse diesel engine, here’s what you need to know about it.

GM 6.6 L Engine Review

GM 6.6 L Duramax Engine Review [hide]

GM 6.6 L Duramax Engine Specs

GM 6.6 L Engine Review

The Duramax diesel engine is a General Motors V8 engine that was introduced in 2001. It is available in the Chevrolet Silverado and GMC Sierra pickup trucks. The Duramax engine is also available in the Chevrolet Express and GMC Savana full-size vans.

  • EGR Valve: Yes
  • Boost Pressure: 29 psi
  • Rated Horsepower and Torque: 325 hp @ 3,000 rpm; 700 Nm (516.3 lb-ft) @ 2,000 rpm
  • Cylinders: 6 in line
  • Valves per cylinder: 4 overhead camshafts, 2 intake and 2 exhaust valves
  • Intake Manifold Construction: individual port fuel injection (not common rail)
  • Turbocharger(s): single variable-geometry turbocharger (VGT), water cooled
  • Exhaust System: stainless steel Catalytic Converter integrated into the manifold; particulate filter with regenerating capability for reduced polluting emissions and extended service intervals.
  • Engine Management System: selective catalytic reduction (SCR) for production of less polluting exhaust gases and long oil change intervals.
  • Emissions Controls: Diesel Exhaust Fluid (DEF) is injected into the exhaust to reduce the amount of nitrogen oxide (NOx). The fluid injection system forces DEF through a metering pump, atomizing injector and common rail. A high pressure pump pressurizes the fluid in a closed loop with an electronic solenoid valve controlling fluid flow into the exhaust stream. The high pressure EGR cooler cools and liquefies the DEF that is injected into the exhaust manifold to be drawn back into the engine where it condenses and separates from other engine fluids before being routed back to storage.
  • Alternator: 12 V, 100 A
  • Battery: one 12 V 400 CCA with standard battery run-down protection and retained accessory power
  • Drivetrain: integrated with transmission. Single piece shaft from engine to dual pinion type rear differential.

6.6 L Duramax Engine Overview

The GM 6.6 L Duramax is a common diesel engine found in heavy duty trucks and SUVs, including Chevy Silverados and GMC Sierras. At first glance you might mistake it for an over-sized version of the 5.7 L LS1 V8 it shares some similarities with , but on closer inspection its differences become clear. The Engine uses two turbochargers instead of one like the LS1, has 2 valves per cylinder (vs 4 for LS1) and features high pressure oil pumps. Also, instead of using pushrods like the LS1 does it utilizes overhead cams – each cylinder head holds one camshaft that actuates either 7 intake valves or intake valves depending on which head you are looking at.

The engine made its debut in 2001 and there have been a few iterations over the years – the current version is the LML. The “L” designation stands for “long”, as the engine has been lengthened by about an inch since its inception to help reduce vibration. The Duramax name comes from the Duramax diesel fuel system which GM developed specifically for this engine.

One of the big selling points of this engine is that it is a common platform – meaning that many components (such as heads, blocks and turbos) can be swapped between different trucks and SUVs with very little modification, making it easier and cheaper to maintain. Additionally, because it’s a diesel engine it is much more durable and can accept a much higher power output.


6.6 L Duramax Engine reliability

The GM 6.6 L Duramax engine is known for its reliability. In fact, it’s one of the most reliable diesel engines on the market. That’s why so many truckers and commercial drivers rely on it.

When properly maintained, the Duramax engine can last for hundreds of thousands of miles. It’s also capable of pulling heavy loads without breaking a sweat. So if you’re looking for a powerful and reliable diesel engine, the Duramax is a good option to consider.

If you’re thinking about buying a truck with a Duramax engine, be sure to have it thoroughly inspected by a mechanic before you buy it. This will help ensure that there are no underlying problems with the engine or major issues with the vehicle.


6.6 L Duramax Engine Key Features

The GM 6.6L Duramax diesel engine is one of the most popular engines on the market today. This powerful engine is used in a variety of GM vehicles, including heavy-duty pickups like the Chevrolet Silverado and GMC Sierra. The Duramax engine features direct fuel injection, a turbocharger, and an intercooler. It also comes with a five-year/100,000-mile warranty.

  • The Duramax engine is known for its high performance and fuel efficiency. In fact, it has won the prestigious International Engine of the Year award. So, if you are looking for a powerful diesel engine that offers great fuel economy, the Duramax engine is a good option. So, if you are in the market for a new heavy-duty pickup truck, be sure to consider the GM 6.6L Duramax diesel engine.
  • The GM 6.6 L Duramax Engine is a 12-valve design with two cast iron cylinder heads and two centrally located camshafts. The engine was designed to make best use of available space, giving it an overall compact size while using state-of-the art technology that gives drivers outstanding performance in many roles—from pulling heavy loads to high-speed interstate cruising.
  • Aerodynamic diesel truck engines are no easy task, especially when they’re expected to haul up to 16,000 lbs (7257 kg) in some configurations. So the engineers focused on making the 6.6L Duramax V8 more aerodynamic than any other diesel truck motor ever produced by General Motors—including the legendary Detroit 6V92.
  • The Duramax also features an electronically controlled high-pressure common-rail fuel system with Bosch CP4 injection pumps and solenoid valves. This system allows up to eight injections per combustion event, providing excellent precision and control over the fuel delivery process.
  • The engine has a cast iron cylinder block and head, integrated cooling module, and thermostatically controlled cooling fan. It is also equipped with an electronic throttle control (ETC) for fast response and smooth acceleration. The ETC is calibrated for optimum performance in all driving conditions.
  • The 6.6L Duramax is backed by a comprehensive warranty, including a five-year/100,000 mile limited powertrain warranty and a seven-year/100,000 mile limited corrosion warranty.

These are just a few of the features that make the 6.6L Duramax Engine one of the best in its class. Drivers who choose this engine will enjoy many years of reliable service and outstanding performance. Thanks for choosing GM!


6.6 L Duramax Engine Horsepower

The Duramax engine has a displacement of 6.6 liters and produces more than 300 horsepower and 520 pound-feet of torque. It is a turbocharged, direct-injection engine with a cast-iron cylinder block and aluminum cylinder heads. The engine features an intercooledturbocharger, common-rail fuel injection, and six-speed automatic transmission.

The 6.6L Duramax is available in two power levels: the LBZ produces 360 horsepower (270 kW) and 650 lb·ft (880 N·m) of torque, while the LLY produces 325 horsepower (240 kW) and 620 lb·ft (830 N·m) of torque. The engine was facelifted in 2006 with the LBZ producing 390 horsepower (290 kW) and 735 lb·ft (997 N·m). The LLY was replaced by the LMM in 2007. The engine was further facelifted in 2010 with the LML producing 397 horsepower (296 kW) and 765 lb·ft (1044 N·m).


6.6 L Duramax Engine Oil Viscosity

GM recommends a  15W-40 viscosity grade engine oil in all instances that the ambient temperature remains greater than 0° F. If the ambient temperature is below 0° F, a 5W-40 engine oil is required to maximize protection during cold starts and the engine warm-up period.W-30 viscosity oil for the 6.6 L Duramax engine.

Some owners have found that a 0W-40 or 5W-40 weight oil provides better performance in cold weather. However, using a heavier weight oil than specified may affect fuel economy and increase wear on the engine.

Choose the weight of oil that is best suited to your driving conditions.


6.6 L Duramax Engine Oil Capacity

The Duramax engine has a maximum capacity of 9.2 quarts without the filter being replaced, and with an improved one it can go up to 10.2 quarts. The oil filter on the LMM is a cartridge-type that requires removal of the entire filter housing to be replaced. GM specifies an engine oil capacity of 9 quarts when servicing the vehicle. It’s important to use the correct type and weight of engine oil in these engines, as they are prone to cavitation and shearing if not properly lubricated.

A variety of oils are available for this engine, both synthetic and non-synthetic. Many owners prefer to stick with a high-quality synthetic oil in order to extend the life of their engine. However, using a non-synthetic oil that meets the GM specification will also work well provided it is changed according to the recommended interval.

Best Oil for 6.6 L Duramax Engine

GM 6.6 L Engine Review

One of the most popular questions we receive at our shop is what the best type of oil is for a GM 6.6 L Duramax engine. There are many options on the market, so it can be difficult to decide which one is right for your vehicle. In this article, we will discuss the different types of oils available and recommend the best one for your needs.

First, let’s take a look at the different types of oils available. The most common type of oil is conventional oil. It is made from refined crude oil and has been in use for many years. It is relatively affordable and provides good lubrication for engines. However, it does not offer as much protection against wear and tear as other types of oil. So, the manufacturers give their preference to full synthetic oils. Check your owner’s manual to make sure of the oil type you need.

When it comes to picking a brand, nearly any brand of oil will do as long as it’s the correct weight; however, GM does prefer that its customers use ACDelco GM Original Equipment Full Synthetic Motor Oil. But car owners often use other trusted brands.

If you are looking for an oil that meets all of these requirements, we recommend Shell Rotella Heavy Duty Diesel Oil. This oil is available at most automotive stores and has been specifically designed for high-output, turbocharged diesel engines. It meets or exceeds the API Service CJ-4 specification and is certified to the IOSF TC-W3 standard.

Customers often choose other trusted brands. These choices also have positive revies:

Valvoline Premium Blue SAE 15W-40 Diesel Engine Oil

Mobil Super 15W-40 Delvac Motor Oil1

Royal Purple Duralec Super SAE 15W-40 API CK-4 High Performance Diesel Motor Oil

GM models using 6.6 L Duramax Engine

GM 6.6 L Engine Review

GM 6.6 L Duramax engines are some of the most popular diesel engines in the world. They are used in a variety of vehicles, from large trucks to passenger cars.

When it comes to diesel engines, the General Motors 6.6 L Duramax is one of the best in the business. If you’re looking for a vehicle that can handle some serious hauling or towing, then this engine is definitely worth considering. Let’s take a closer look at what makes the Duramax so impressive.

The Duramax was first introduced back in 2001, and it’s been continually refined and improved over the years. It’s now available in a wide range of vehicles, including pickup trucks, SUVs, and even commercial vans.

The 6.6L Duramax diesel engine (VIN code “L”) is used on 2010 interim and 2011 Chevrolet Express and GMC Savana vans and 2011 Chevrolet Silverado and GMC Sierra trucks with RPO ZW9 (chassis cabs or trucks with pickup box delete).

GM 6.6 L Duramax Engine life expancy

GM 6.6 L Engine Review

The Duramax 6.6L V8 Turbo Diesel Engine is sold with a warranty of 100,000 miles/160,000 kilometers. The Duramax has been tested to survive upwards of 200,000 miles/320,000 kilometers. The Duramax powertrain is designed for reliability, peak horsepower and torque within its design limits.

So, many Duramax owners report that their engines have easily passed the 200,000 mile mark with few major problems. The only major issue that has been reported is failure of the high-pressure fuel pump, which can be expensive to replace. Overall, the GM 6.6L Duramax diesel engine is a reliable and durable engine that can provide years of service.

Common Issues with 6.6 L Duramax Engine

GM 6.6 L Engine Review

The 6.6 L Duramax V8 truck engine was introduced by the Chevrolet Silverado, GMC Sierra, and Isuzu N series in 2003. Since then, it has become more popular than ever with its powerful torque capacity and improved gas mileage. However, like any other vehicle of this age there are some common issues that owners must deal with. Here is a list of the known problems associated with the 6.6 L Duramax engine:

  • Leaks (most often oil but can be coolant or fuel)
  • Excessive Oil Consumption (due to internal wear which causes the valve stem seals to fail)
  • Cracked Exhaust Manifolds
  • Turbo Failures
  • Electrical Issues
  • Truck Loses Power or Stalls While Driving
  • Fuel Gauge/Odometer Not Working As Usual

Leaks are among the most common problems with these engines. The most typical of these is an oil leak, but there have also been many reports of coolant and even fuel leaks. If not fixed promptly, these can lead to major engine damage due to corrosion on the components around where the fluids drip onto. Unfortunately, even if taken care of immediately, some owners have had no choice but to replace their engines because of excessive wear underneath where the oil was dripping onto.

GM 6.6 L Duramax Engine Location

GM 6.6 L Engine Review

The GM 6.6 L Duramax engine is located at the front of the truck, under the hood. The engine is long and narrow, and takes up a good amount of space in the engine bay. It is a V8 engine, and has two turbochargers. There is a lot of wiring and plumbing running to and from the engine, so it’s important to have a good understanding of how all of it works before starting to work on it.

Replacing GM 6.6 L Duramax Engine

Do you still think replacing a GM 6.6 L Duramax engine isn’t worth it? Well, for those of you who are considering doing the job by yourself , here is a helpful article that will show how you can do everything from removal to installation on your own car. The following steps will not only make this task easier for you but also make it less time-consuming and require fewer tools.

  1. Disconnect the negative battery cable to prevent an accident, first disconnect the negative battery cable as it could provide power to the fuel pump which stays on after shutting off the ignition switch. This could cause a fire or explosion if any sparks occur near gasoline vapors. Also, sure to have all essential items handy.
  2. Remove the engine’s oil filter. This is an essential step for this job since you will not be able to remove the filter later when it blocks access to it. The oil filter can be removed by either using a tire-iron tool or simply turning it counterclockwise until its separated from the block, followed by taking out the old one and replacing with a new one.
  3. Disconnecting fuel lines & wiring harnesses. Do not worry about draining out the gas from the fuel lines because there will be no pressure to do so. Just disconnect the wiring harnesses on top of both fuel rails by undoing 4 fasteners on each rail, followed by pulling back on the locking tabs on both sides of each connector.
  4. Disconnect transmission cooler line. This is a step that most people forget about but it’s important to do this job first since you won’t have any room to work with once your engine is separated from its mounts later. On the driver side of the vehicle near where engine mounts connect, disconnect the large radiator-like part before pulling it away from hoses coming out of it and unbolting these hoses one by one. Afterwards, remove the metal bracket that is holding it in place to free yourself from any unnecessary obstacles.
  5. Disconnect engine mounts. Before disconnecting engine mounts, you will need to take off air cleaner assembly which can be done by removing 4 bolts on top of it followed by simply pulling it out. Once it’s removed, do the same thing on driver side (3 bolts) and passenger (2 bolts). You may need to release other parts after this like steering shaft, ABS sensors(if equipped), etc., but make sure to write down how these parts go back together. Also, don’t forget about the various bolt sizes for different parts; otherwise you might end up putting them back to their original locations or worse- breaking them! After everything is disconnected, it should be relatively easy to separate the engine from its mounts by pushing & pulling on it.
  6. Removing the engine. There are several ways of removing an engine but we’ll just be focusing on one method which is using a hoist. The most important thing is to have the right measurements so that your hoist can actually fit under the car. Once you have determined that, loosen the nuts (or bolts) on the front crossmember using a socket wrench and jack up your car until the engine mounts are no longer in contact with the ground. From there you can use your hoist to lift up your engine and carry it out from underneath.
  7. Installing new engine. This part is pretty self-explanatory but just make sure that you have all of the bolts, washers, and nuts in the correct sizes and that they are properly tightened before moving on to the next step. Also, don’t forget to reconnect all of the wiring harnesses, fuel lines, and transmission cooler line before putting everything back together!
  8. Reconnecting air cleaner assembly. Once you have the engine in position, go ahead and reattach air cleaner assembly by bolting it back in place and tightening its bolts. Make sure that you put everything back where it originally was before tightening so there’s no guesswork involved.
  9. Reinstalling engine mounts. This part can be a little tricky if you’re not familiar with how the engine mounts were put in initially. If they are the same type of mounts that have already been taken off, just remember to tighten them using a torque wrench and it should be easy to install.
  10. Reconnecting brake lines. Last but not least, connect your brake lines back onto your new engine so you can drive away without worrying about squishy brakes! These are by far the trickiest parts because there are so many different kinds of connectors for both steel & rubber hoses plus every car is different. Your best bet is to look up diagrams online or good old trial-and-error but make sure that you don’t cross any threads or anything like that when connecting them otherwise pressure will build up under your car or in the line and make it burst which is not good.
  11. Putting everything back together. Once all of your parts are connected, tighten everything back up and make sure that you secure the engine mounts properly by using a torque wrench; don’t rely on instinct. Also, put everything else back to where it was before like transmission, exhaust system, gas tank (don’t forget about fuel lines), etc.

Replacing a GM 6.6 L Duramax engine is not a difficult process, but it can be time-consuming. The first step is to disconnect the air cleaner assembly, followed by the brake lines. Next, remove the engine mounts and disconnect the wiring harnesses, fuel lines, and transmission cooler line. The engine can then be lifted out from underneath the car. The new engine can be installed in reverse order, making sure to reconnect all of the parts and tighten everything securely. Finally, put the car back together and you’re good to go!

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