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LMM Duramax Glow Plugs

LMM Duramax Glow Plugs

LMM glow plug control module

We know that even though glow plugs are not mandatory for your vehicle’s engine to start up, they play quite a role in cold weather. Now they seem a bit more important, don’t they? The LMM Duramax engine will need eight glow plugs to work properly as a unit. But who will control them?

We have the glow plug control module or the glow plug controller for this particular task. The glow plug control module or controller will control how much heat the glow plugs will produce, when or how the glow plugs will become active, which one will be up to the task, how much current will flow to each glow plug, etc.

LMM Duramax Glow Plugs

So, the glow plug controller is as important as the glow plugs. Because without the module, the engine won’t be able to use the glow plugs. That is why a damaged or wore out glow plug control module is not a nice thing to have in your vehicle. Especially in the cold weather.

What do you do then? You need to change the glow plug control module with an aftermarket one. You will know about a damaged control module by mainly error codes that refer to glow plug-related problems.

Check the glow plug control module of your LMM Duramax if you see the symptoms. After the confirmation, go for the replacement. You will need around $250 for the control module alone. And save some extra for the labor cost.

LMM glow plug order

Knowing the order of the glow plugs or their location is very important if you want to replace them. Because if you don’t, you will face trouble replacing them. Chances are you might replace the wrong one. In order to know the glow plug order, you need to know the location of the cylinders.

As there is one glow plug for every cylinder, you will know the location of the glow plugs if you know the location of the cylinders.  The cylinders are in such a location, it is very easy to locate them and remember their location. 1, 3, 5, and 7 number cylinders are on the passenger side. And 2, 4, 6, and 8 number cylinders are at the driver’s side.

That means the even-number cylinders are on the driver’s side and the odd-number cylinders are on the passenger side. And for your information, the firing order of the cylinders is 1-2-7-8-4-5-6-3.

Duramax glow plug location

Knowing the location of the glow plugs is very important in case of any replacement. The location of glow plugs on Duramax is very common. If you can get to the cylinders, you can get to the glow plugs too.

duramax glow plug location

Basically, you can find the glow plugs of Duramax engines if you remove the wheel fender liners. The odd number of glow plugs are on the passenger side and the even numbers are on the driver side. Try to go for the passenger side at first as this side’s glow plugs are easier to get to. And then go for the driver-side glow plugs if there is any problem or for the sake of any diagnosis.

Duramax glow plug location diagram

Duramax Glow Plug Location Diagram

It might be hard for you to find out the location of the glow plugs by just reading the information. It will be better if you can visualize the location with a picture or a diagram. Watching a video will be more useful. We are attaching a diagram here to help you visualize the location of the glow plugs better.

2011 Duramax glow plug diagram

In 2011, there were three running Duramax engines. They were LGH, LML, and XLD25. That is why it is quite tough to know the correct information about the 2011 Duramax engines. You have to be more specific in this regard.

For instance, XLD25 is not even a V8 engine. It is an I-4 engine. Anyway, we are attaching a diagram in this section so that you can visualize the location of glow plugs of 2011 Duramax engines in a better way. The glow plugs shown in the diagram are passenger-side glow plugs.

Duramax glow plug replacement cost

The actual cost of glow plug replacement varies. It depends on various factors. The location, vehicle model, and shop. It also depends on whether you want to do it on your own or by a mechanic. 

You will need around $12-$20 for a new glow plug. If you want to replace all eight glow plugs of your Duramax engine, you will need around $100-$160. And the labor cost will be in between the range of $100 to $200. To sum up, you will need around $200 to $360 for a full set glow plug replacement. 

Is It Ok To Run The Duramax With A Bad Glow Plug?

The short answer is no—it isn’t. In the case of Duramax engines, running the engine with one or more faulty glow plugs can cause damage to the engine, resulting in higher repair costs and decreased reliability. A malfunctioning glow plug can even trigger a catastrophic engine failure in the worst-case scenario.

How Many Glow Plugs In A 6.6 Duramax

The 6.6 Duramax has eight glow plugs, four on each engine side. These glow plugs provide enough heat for the engine to start quickly, even in cold temperatures. The glow plugs will shut off when the engine warms up, saving energy and fuel.

How Many Glow Plugs Does A Duramax Have

The Duramax requires 8 plugs, with one in each cylinder. These plugs should be replaced approximately every 100,000 miles or 150,000 kilometers. 

How To Test Glow Plugs Lly Duramax

Testing your glow plugs on a Duramax LLY engine is fairly straightforward. Here’s a step-by-step guide for testing and replacing the plugs on your Duramax LLY engine:

  1. Disconnect the negative battery cable.
  2. Unplug the glow plug wiring harness from the glow plugs.
  3. Test the glow plugs one at a time. To do this, reconnect the negative battery cable first, then measure the voltage at the two contacts of each plug while the engine is running. If the voltage measured is 0.2 volts or lower, it indicates a bad glow plug.
  4. If your glow plugs need to be replaced, consult your owner’s manual to ensure you’re using the correct type for your engine, and then replace them one at a time. Be sure to torque the glow plugs to the correct specification.
  5. Reconnect the wiring harness.

Your Duramax LLY engine should now have spark-free and efficient glow plugs that should make starting the engine easier and help keep you running smoothly.

Can a diesel run without glow plugs?

Yes, a diesel engine can run without glow plugs – but only in certain conditions. A diesel engine can perform compression ignition without glow plugs if the temperature outside is high enough and the engine has enough compression. 

Do new glow plugs improve performance?

The answer is a resounding yes! Glow plugs are small but potent components of your car’s engine that heat your fuel so that it burns more efficiently. This leads to better fuel economy, more decisive acceleration, and higher overall performance. 

Not only do new glow plugs bring your car much-needed performance improvements, but they also make a great environmental statement. 

Can faulty glow plug damage engine?

The short answer is yes. Faulty glow plugs can cause significant damage to an engine. They can lead to various problems, ranging from fuel inefficiencies to complete engine failure.

When a glow plug is faulty, it can draw too much power and cause the engine to overheat. This can lead to engine misfires and damage to the fuel injector, pump, and pistons. In extreme cases, it can even cause the valves to become warped, leading to costly repairs.

Should I replace one or all glow plugs?

The answer depends on the make and model of your vehicle. In some vehicles, each plug is responsible for a particular cylinder, and it may be necessary to replace all of them if the engine is misfiring or running rough. However, all plugs may be the same on other vehicles, meaning you just need to replace one to get the engine running properly.

Are glow plugs only used for starting?

The simple answer is yes. Glow plugs are specifically designed to help a diesel engine start in cold weather conditions as they heat the necessary components to get the engine going. 

Can glow plugs drain the battery?

In most modern vehicles, the glow plugs are designed to draw very little current. The onboard computer systems of these vehicles efficiently control the glow plugs, thus ensuring that they draw only the amount of current they need to do the job.

However, older cars and vehicles with worn-out glow plugs draw too much current as they may be faulty or damaged. In such cases, the glow plugs can drain the battery over some time.

Can you clean glow plugs?

The short answer is yes! It is possible to clean glow plugs to extend their life and reduce costs in the long run. The process isn’t too difficult and will require you to have a few essential pieces of equipment on hand. The first item you’ll need is a can of compressed air. This will be used to blow away dust, dirt and any rust that has built up on the glow plugs. 

Next, you’ll need a steam and pressure cleaner. These are typically used to clean various engine components including glow plugs. You can then use the steam cleaner set to a medium-pressure setting with a spray attachment to blast away any remaining debris.

changing Duramax lmm glow plug replacement

LBZ glow plug part number  

The part number of an LBZ Duramax glow plug is #97364968. You may also see the part number as GM Part #97364968 and it is 61G. 

Are you ready to replace your Duramax glow plugs for LB7 Chevy / GMC Duramax

lmm Duramax glow plug torque spec

LMM Torque Specs

LMM Aftermarket Fastener Torque Specs
Glow Plug13 lb ft
Glow Plug Controller Bolt89 lb in
Glow Plug Harness Bracket Bolt89 lb in
Glow Plug Nut18 lb in


Does an LMM have glow plugs?

Yes. LMM Duramax uses glow plugs. It does not use spark plugs as it is a diesel engine. You need to use glow plugs instead of spark plugs because the starting process of a diesel engine and a gas engine is totally different. As a V8 engine, LMM Duramax needs eight glow plugs to work properly as a unit. 

How long do glow plugs last Duramax?

You can expect a rough number of around 100,000 miles. The glow plugs may last longer or shorter depending on your driving habit. However, you don’t need to change them every 100,000 miles. Because they are different from the likes of spark plugs. You can let them stay as long as you don’t see any symptoms of a glow plug failure. 

What are the symptoms of glow plug failure?

The most common symptoms of a glow plug failure are-

  • Rough idling
  • Misfire from engine
  • Bad fuel efficiency 
  • Hard starting
  • Black smoke
  • White smoke

 Where is the number 1 glow plug on Duramax? 

The number 1 glow plug is on the passenger side of the vehicle. Numbers 1, 3, 5, 7 are on the passenger side. That means the odd number of glow plugs are on the passenger side. You can reach there either by removing the fender liners or from the top. 

Where is the number 2 glow plug on Duramax?

The number 2 glow plug is on the driver’s side if the engine is Duramax. Basically, 2, 4, 6, 8 number glow plugs are on the driver’s side. So, we can tell all the even number glow plugs are at the driver’s side of the vehicle. 

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