5 Most Common LMM Duramax Problems | Expert Advice And Fixes

LMM Duramax is a high-quality engine with a unique emission feature. Even though this engine is from the late 2000s, it still works efficiently. Supporting and improving a wide range of cars worldwide. 

LMM Duramax engine may show problems over time due to wear and tear after daily use is natural. A lot of issues can cause an engine to malfunction. One common problem to keep an eye out for is an overheating engine. 

Thus, taking care of the engine is important. Maintaining properly prevents your engine and car from harm. If you want to learn more about LMM Duramax problems and how to fix them, then stick to the end.

Duramax LMM Engine Specs And Overview

Manufacturing years of LMM Duramax lasted from 2007 to early 2011. The specs of this engine are quite upgraded compared to its previous models. 

With good all-round features, the LMM Duramax engine doesn’t disappoint. Specifications which make the engine better are:

Design6.6L Duramax Diesel
Transmission6-Speed Auto Allison Transmission
Weight835 Lbs
Crankshaft materialManufactured Steel
Oil Capacity8.70645 liters
Size of fuel tankShortbed is 26 gallonsLongbed is 32 gallons
Torque660 lb

Which Cars Model Has LMM Duramax Engine?

LMM Duramax is an excellent reliable engine offering stability to cars all over the world. It is installed in various types of vehicles, to ensure better performance. Several stats significantly increase when LMM Duramax is attached. The cars which use LMM Duramax are-

GMC Chevrolet Silverado 2500 

GMC Chevrolet Silverado 2500

Chevrolet Silverado 2500 HD trucks were manufactured during 2007-2010. It’s quite a popular truck that came with the latest LMM Duramax engine around that time.   

LMM Duramax enhances the performance of the Chevrolet Silverado 2500 HD. It offers a diesel particulate filter [DPF] system. A DPF’s job is to capture excessive exhaust soot and burn it off through a regeneration procedure.

GMC Sierra 1500 (2007-2010)

GMC Sierra 1500 (2007-2010)

GMC Sierra is almost the same truck as Chevy Silverado. They are both made by the same company GMC, from the years 2007 to 2010. Both of these cars have their engine in common which is the LMM Duramax. 

Along with the DPF system, the built-in revised injectors of this engine benefit the car. Improved injectors provide more complete combustion and power.

GMC Chevrolet Kodiak 

GMC Chevrolet Kodiak 

It is a high-capacity truck able to carry heavy loads. Within an affordable price range, Chevy Kodiak offers improved HP due to LMM Duramax. The manufacturing of this model was discontinued in 2009. And production started in 2007.

Chevrolet Kodiak takes advantage of the LMM Duramax’s increased exhaust gas circulation. Other benefits featured above about different vehicles are also applied in Kodiak.

GMC Savanna (2011-2016)

GMC Savanna (2011-2016)

Even though this car exceeds the production years of the LMM Duramax engine, it still has it. LMM Duramax was also produced in early 2011. It is a good van with nice handling and controls.

With LMM Duramax the nitrogen oxide emission is reduced because of its advanced emission system. Which also includes better combustion.

What Are The Signs Of LMM Duramax Issues?

Most of the time you will get notified about the existing problem until something bigger happens. As a result, knowing about the symptoms beforehand will aid you in treating the issue. Here are signs you could see bothering your car:

  • Overheating engine
  • DPF not working properly
  • P0087 Diagnostic trouble code[DTC] might pop up
  • Engine making noises due to damaged piston
  • Broken crankshaft 
  • Leak in transmission fluid line

5 Most Common LMM Duramax Problems

Noticing the symptoms will help you detect the problems. LMM Duramax life expectancy is quite long as people are still using it for a decade. This long-lasting engine can often suffer from problems due to wear and tear. The common problems of the LMM Duramax engine are:  

1. Piston Failure 

LMM Duramax’s pistons are prone to high horsepower. As it is one of the most common issues. The pistons are fragile. If horsepower exceeds the limit it breaks. 

Excessive sounds from the engine are a result of broken pistons.

2. Transmission Fluid Line Leak

Another common issue is a leak in the transmission fluid lines. Transmission fluid lines are responsible for carrying coolants to the engine. As a result, due to insufficient cooling, the engine gets overheated.

3. DTC P0087

Diagnostic trouble code P0087 is also a generic engine problem. This code indicates various problems. Such as clogged fuel injectors or faulty fuel pumps.

4. Damaged crankshaft

Possibly the crankshaft could be broken. A crankshaft failure is a fault bad enough to stop an engine from working. During a faulty crankshaft, the engine light will turn on to notify you.

Also, watch out for engine vibration. In the case of a damaged crankshaft, the engine often vibrates and misfires. As a result, there is difficulty in starting the vehicle. 

5. DPF malfunctioning

If you see a warning light on the dashboard, that means your DPF isn’t in good condition. To recognize the type of light, read the owner’s manual for further knowledge.

Because of this issue, the fuel consumption rate of your car may rise more than usual. A broken DPF causes excess soot build-up in the exhaust system. Thus, look out for the signs to detect DPF issues. 

How To Fix LMM Duramax Problems?

To fix LMM Duramax problems first you need to identify the problem. After that, it’s time to take action. Learn how to tackle LMM Duramax problems by yourself by following these easy steps below:

Check for leaks in transmission fluid lines

If your engine overheats, then there is a leak in the transmission fluid lines. So start looking for the leaks. Fix the leak when you locate it.

Fix the engine’s pistons if it is faulty

The engine can sometimes make noises if your car stands idle. When you notice these noises, stop your car and examine your engine. If your piston is damaged, repair or replace depending on the condition. Give the owner’s manual a quick read for further knowledge of engine parts.

Check the hood if you see DTC P0087

Code P0087 alarms the driver about certain engine issues. Check the fuel injectors and fuel pumps. The fuel injectors could be jammed with dirt. If that’s the case, detach the injector. Attach the injector back again after you clean it.

The fuel injector may be working fine. That means you should check the fuel pump for damage. A damaged fuel pump always needs replacement. Driving with a faulty pump ruins car performance.

Repair or replace the broken crankshaft

Sometimes rather than the pistons the crankshaft’s condition could be worse. Replacing a crankshaft is expensive. If its condition is not very bad, consider repairing it. Notice the cracks on the crankshaft. Reinforce the coating of metal if it is distorted.

Clean your engine’s DPF

Due to regular use of your car, a DPF gets prone to dirt. Dirt and debris often clog up the DPF. That’s why DPF has its regeneration system. Which allows itself to clean excess soot. Eventually, this puts pressure on the engine and the DPF gets clogged. So clean your DPF at regular intervals to maintain its condition.

Also read our guide on- LML Duramax Problems

LMM Duramax Maintenance Guide

It is important to take regular care of your engine. Proper maintenance ensures that your engine performs well during critical situations. Thus, protect your engine from possible threats by following these steps below:

Replace the engine oil from time to time

Replacing engine oil prevents wear and tear from greatly affecting your engine. The oil lubricates all the parts. As a result, keep the amount of oil in check. Low oil levels increase friction among parts.

Fix the oil filter when it’s necessary

Oil filter is responsible for cleaning all the dirt and debris from the oil. It makes sure that clean oil goes through the system. Thus, clean or replace your oil filter if it gets too dirty.

Check your air filter

Keep an eye on your air filter’s condition at regular intervals. Improper filtration lets the dirt carried by air get into the system. Which slowly jams the parts, preventing them from moving smoothly.

So clean your air filter routinely. Due to this clean air will be free to enter the car.

Pay attention to checking the engine light notification

Your car can give you notifications on the dashboard. If your car notifies you to check the engine light, don’t ignore it. In this case, the car is warning you about potential engine issues.

It is wise to stop your vehicle when you see the warning. Then examine the engine to fix the problem.


LMM Duramax is a well-balanced engine with attributes that improve your car significantly. However, there are some common misconceptions about this product. Some frequently asked questions about this engine are:

Is the LMM Duramax reliable?

Yes, LMM Duramax is a very reliable engine. With appropriate maintenance, it works smoothly. This engine will not disappoint you during all sorts of driving situations as you can tune it as you like.

How Long Will an LMM Duramax Last?

This engine can last up to 300,000 miles until wear and tear start to affect it. Although if taken care of properly, LMM Duramax can survive up to a max limit of 500,000 miles or more. 

What Year Is LMM Duramax Best?

2007-2010 were LMM Duramax’s golden years. During these three years, production and demand were high. Various types of vehicles were making use of this engine.

How Much Horsepower Does LMM Duramax Have?

LMM Duramax engine comes with a horsepower of 365. For basic to high-speed driving, hp between 200 to 300 is pretty good. If you want to push your car to the limit you can also go over 300hp. 

Does LMM Duramax Have Def?

The later models of LMM Duramax at the start of 2011 had DEF[Diesel Exhaust Fluid]. DEF has the job to reduce the amount of nitrous oxide released by a car.


In today’s modern era it is still okay to use the LMM Duramax engine in your car. As this engine almost meets all the common needs of all drivers.

Just make sure that you do a routine check on your engine. Maintaining the engine in tiptop shape will increase its durability, reliability, and longevity.

Although, sometimes we have less time to fix these problems by ourselves. If that’s the case feel free to go to your local auto repair shop for assistance.

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