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How Much Diesel Exhaust Fluid Does A Duramax Hold?

Duramax needs diesel exhaust fluid (DEF) to run efficiently like any diesel. But how much diesel exhaust fluid does the Duramax hold? Let's take a look.

Depending on your Duramax engine, the DEF capacity will range from 5-7 gallons. The best way to keep track of your DEF levels is to check the gauge on the dash.

You can also check your owner manual for the specific DEF tank capacity.

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Knowing the level of DEF in your tank is important because if it runs too low, the engine will go into "limp mode."

This article will discuss how much diesel exhaust fluid your Duramax needs. In addition, we will answer other frequently asked questions about diesel exhaust fluid, so read on!

Adblue diesel exhaust fluid DEF and diesel fuel tank cap, How Much Diesel Exhaust Fluid Does A Duramax Hold?

What Is The Capacity Of A Duramax DEF Tank?

After 2010, diesel engines were required to use diesel exhaust fluid (DEF) to meet the strict NOx emissions standards set by the EPA. As a result, all Duramax engines come with a DEF tank.

The capacity of the DEF tank on a Duramax engine will depend on which model year and engine you have. For example, most Duramax engines made from 2011-2016 have a DEF capacity of 5 gallons.

However, the 6.6-liter Duramax engines made after 2016 have a DEF capacity of 7 gallons. Then the vehicles equipped with the 3.0-liter Duramax engine have a DEF capacity of 5.4 gallons.

You can check your owner's manual to find the specific DEF capacity for your Duramax engine. You can also find the DEF tank capacity by looking at the sticker inside the fuel door.

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You can also check your DEF levels by looking at the gauge on the dash. The DEF gauge is usually located next to the fuel gauge.

If you buy a used Duramax, you should ask the seller about the DEF tank capacity. This way, you will know how much DEF you need to add to the tank.

You should also ensure that the previous owner was diligent about adding DEF to the tank. If not, the engine may have been damaged and need to be repaired.

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Where Do You Fill The DEF Tank On A Duramax?

The DEF tank on a Duramax is usually located next to the fuel tank. You can find it by looking for the blue cap with "DEF" on it.

Once you fill the DEF tank, check the gauge on the dash to ensure it reads full. You can also check if a specific message on the dash says "Add DEF."

There are also different diesel exhaust fluids, so check if your diesel vehicle needs a specific kind of DEF. You can usually find this information in the owner's manual.

If you are unsure about which type of DEF to use, you can always ask the experts at your local auto parts store. They will be able to help you find the right type of DEF for your Duramax engine.

Lastly, you can see what the dealer recommends when you take your Duramax for service. They will be able to tell you what type and how much DEF you need for your specific engine.

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What Happens If You Don't Use DEF In A Duramax?

If you don't use DEF in your Duramax, the engine will go into "limp mode." This means the engine will run at reduced power, and the vehicle's speed will be limited.

Limp mode is triggered when the DEF tank is empty or there is not enough DEF in the tank. When this happens, a message will appear on the dash that says "Add DEF."

If you continue to drive without adding DEF, the engine will eventually shut down. This is to prevent damage to the engine.

If you accidentally run out of DEF, you can usually restart the engine by adding DEF to the tank. However, you should take your vehicle to a dealer or mechanic to have it checked out.

If your diesel vehicle is under factory warranty, you risk voiding it by not using DEF. This is because not using DEF can damage the engine, and most warranties will not cover engine damage that the owner caused.

It is also important to note that you should never put anything other than DEF in the DEF tank. This includes water, diesel fuel, or any other type of fluid.

Putting anything other than DEF in the tank can damage the engine, and you will likely have to pay for the repairs yourself.

Can You Put Diesel Exhaust Fluid In The Fuel Tank?

refilling the def fluid

It is highly recommended that you not put DEF in the fuel tank. This is because DEF is not combustible and will not burn in the engine.

Putting DEF in the fuel tank can damage the engine, and you will look at high repair bills. The reason is that DEF is corrosive and will eat away at the metal in the engine.

DEF is also designed to break down when it comes into contact with heat. So, if you put DEF in the fuel tank, it will break down and clog up the fuel filter.

This will cause the engine to run poorly, eventually leading to engine failure. If you accidentally put DEF in the fuel tank, you should have the vehicle towed to a mechanic or dealer.

They will be able to drain the fuel tank and flush the engine to remove the DEF.

How Long Does A Tank Of Diesel Exhaust Fluid Last?

On average, you can expect one gallon of DEF to last 300-500 miles. This means the Duramax, which has a 5-7 gallon tank, will need to be refilled every 1500-3500 miles.

However, this will vary depending on how you drive and the terrain.

For example, if you do a lot of stop-and-go driving in the city, you will use up DEF faster than driving on the highway.

It is also essential to remember that the DEF tank will not be empty when the fuel tank is empty. This is because the DEF system only uses a small amount of fluid each time it regenerates the DPF.

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What Is The Shelf Life Of Diesel Exhaust Fluid?

The shelf life of DEF is around two years. However, it is important to note that the fluid will degrade after the first year.

This means you should only buy as much DEF as you need and try to use it up within a year. This way, you know you are getting the full benefits of the fluid.

Storing DEF in a cool, dark place will help it last longer. You should also ensure the container is sealed tightly to prevent moisture from getting in.

Can You Overfill Diesel Exhaust Fluid?

Diesel exhaust fluid additive for trucks

When adding diesel exhaust fluid to your Duramax or any other diesel vehicle, it is important not to overfill the tank.

Overfilling the DEF tank can cause problems with the system and may lead to costly repairs. The reason is that diesel exhaust fluid is mostly water and can freeze in cold weather.

If the fluid freezes, it can expand and crack the DEF tank. So, if you are adding DEF in cold weather, make sure not to overfill the tank.

In addition, the DEF can crystalize in the tube that goes from the tank to the injector. This can lead to clogs and eventually damage the injector.

So, when adding DEF, only fill the tank up to the line or below it. This will help prevent any problems down the road.

What Should You Do If You Run Out Of Diesel Exhaust Fluid?

First off, if you can, try to avoid running out of diesel exhaust fluid. As mentioned earlier, you could have serious problems if you do.

However, if you do find yourself in this situation, there are a few things you can do. One option is to drive to the nearest diesel dealership or service station and purchase some more DEF.

Another option is to see if the local auto parts store delivers DEF. This way, you can have it delivered right to your location. This is a good option if you are stranded in a remote location.

Lastly, your vehicle can be towed to a diesel mechanic or dealership. They will be able to add DEF to your car and get you back on the road.

Final Thoughts

Adblue diesel exhaust fluid DEF and diesel fuel tank cap

Hopefully, this article has helped explain the importance of diesel exhaust fluid and how it works. When in doubt, check the owner's manual for your specific vehicle.

It is always best to err on the side of caution when adding DEF to your vehicle. This way, you can avoid any costly repairs down the road.

Made it to the end? Here are other articles you might find helpful:

When To Add DEF [And How To]

Does DEF Go Bad? [Inc. If Frozen]

What's The Best DEF (Diesel Exhaust Fluid) For Ford F250?