How to Make DEF and Is It Worth Your Effort? We Explain

All new diesel engines are required to work with DEF systems. The abbreviation stands for Diesel Exhaust Fluid and is basically the mix of two components - water and urea. If you own a diesel truck, SUV, semi truck, or some special equipment, you are required to buy DEF and keep some of this fluid in your DEF tank at all times.

Today, we'll tell you whether you can make DEF by yourself or whether it is a bad idea. We'll tell you more about the components, their prices, and the problems you may face in the process. Of course, we'll also make the conclusion in this article and tell you about our own thoughts. This will help you look at the question from different angles and form your own opinion.

Here's what we are going to cover in this article:

• What's essentially DEF and why at all do we need this fluid in diesel vehicles?
• Can you make DEF by yourself and what do you need for this?
• Why is it a bad idea to make DEF on your own?
• What if you keep driving your diesel vehicle without DEF?

Let's get started!

What's DEF and how is it manufactured?

DEF is the special fluid that should be always added to any modern diesel engine to let it work well. The fluid consists of two-thirds clean prepared water and one-third urea. Urea is a component that is formed in the bodies of mammals in the process of nitrogenous breakdown and this is one of the main components of urine. But for commercial use they don't take urine to manufacture urea - they synthesize it with the help of chemical reactions.

So, ironically, DEF is the mixture of water and urine and this is what they make us pay money for! Although this is a joke, it won't sound really funny to those who drive diesel vehicles. Some of them would prefer to pee in that DEF tank rather than pay for that annoying fluid again. But, unfortunately, this will not help.

Here's how they make DEF:

• first of all, they prepare water and clean it in several steps leaving clean and distilled water that can be used in production;
• after that, they synthesize urea using different sorts of chemical reactions and also clean it to avoid any possible damage to the DEF system in your vehicle;
• then, they mix it in optimal ratios - it's not just 2/3 against 1/3, the mixture contains exactly the needed amount of urea, and the measurements are very precise;
• the prepared DEF fluid is then tested in terms of its properties and gets certified;
• only after this step the fluid is packed into plastic canisters or delivered to gas stations to be sold.

There are quite a few companies that make DEF all around the US and all of them are registered ad licensed. Their products are checked and tested all the time at different stages of manufacturing and selling, so the products are guaranteed to be of high quality and will never damage your vehicle.

But you may have seen people selling DEF cheaper than major gas stations and without any canisters that would have at least some information about its origin. So, not all DEF in America is made according to the rules and standards. But is it safe to buy homemade DEF fluid? Or can you at all make it by yourself? Let's see!

Making DEF on your own - is it possible?

It doesn't sound like a complicated task - to just mix 1/3 of urea with 2/3 of water. So why do you still pay for that DEF if you can make it on your own?

Well, the first problem is clear: where can you take urea? You may try to find a manufacturer of urea that would sell it to you cheaper than DEF at a gas station. We tried this online and failed. It's hard to buy clean urea if you are not a big company with a license for manufacturing some urea-based products.

You may think you can make it by yourself! Well, here's how urea is manufactured:

• you will need a special piece of equipment that creates certain pressure and then also heats the products inside it;
• then, you will need natural gas which can be taken from your home or from a special gas station;
• also, the process takes some atmospheric nitrogen and clean water;
• at high pressure and high temperature, these products will react and produce ammonia and carbon dioxide;
• after that, you will need to change the pressure and temperature settings and get liquid urea.

It sounds quite complicated and almost impossible to make by yourself, so this is not the method for everyone. Maybe, you can do that if you are a chemistry specialist and have all the needed equipment. But for most of us, this is too hard to even understand, let alone make.

So, technically, if you know how to buy urea from a chemical company, you can produce your own DEF and save some money. But we doubt if you can save a lot. The average price of DEF is $3-6 for 1 gallon depending on your state and also the brand you prefer. But no one knows how much it will cost you if you only buy urea and prepare your own solution.

One gallon of DEF is enough for 50 gallons of diesel. So, if your diesel truck allows you to go 30 MPG, you will only need 1 gallon of DEF for 1500 miles. Are you sure you will economize a lot if you try making this DEF by yourself?

Why shouldn't you try making DEF on your own?

We don't see any reason why you may want to get your hands dirty and make DEF by yourself. The only possible reason is that you can then sell it to some other people and maybe earn some money. But again, we see a problem with purchasing or making urea, we see a problem with preparing water and testing your final product. Eventually, this doesn't make sense to make so many moves and get nothing back.

Also, you may easily break your DEF system in the vehicle if you prepare a bad or contaminated solution. Also, the efficiency of self-made DEF may be much worse than expected and you may have problems going through fog tests.

Also, we see some other problems:

• this is a chemical product and making it without the proper experience is dangerous for your health;
• buying components for this process is not completely legal for private buyers;
• you may face additional expenses when your DEF system fails in the vehicle;
• you will save a couple of dollars a month, and this is the best estimated result;
• you will most likely not get the full efficiency and may get in trouble with self-made DEF.

So, clearly, there is no reason why you should try making DEF by yourself. We don't see any possible advantage that you will get. Although it's really annoying to pay some money all the time for some water mixed with urine, this is still the only reasonable way you should act if you have diesel cars, trucks, or equipment.

Also, when you buy DEF, be careful and buy only certified products. Otherwise, you will face all those possible problems of the self-made fluid but will also not get any financial gain.

What if you drive without any DEF at all?

Well, in some older vehicles, DEF is an optional thing that people can choose whether they want to use. But those are just exceptions from the common rule that DEF is as important for your vehicle or equipment as diesel fuel or any other fluid that is there in the car like coolant or oil. If you don't have any DEF in the tank, you will not be able to drive most modern diesel vehicles until you refill the tank.

Always have a certain amount of DEF in your vehicle just in case you forget to refill the tank when needed. In most cases, your vehicle will not drive without DEF. What's more, the DEF system may go bad and require some maintenance or repair if you allow the tank to run empty. For example, one of the DEF sensors that controls the quality of fluid may cost over a thousand dollars to replace.

So, refilling DEF is almost as important as refilling diesel fuel in your vehicle. Don't forget about it and better refill it every time you are buying diesel fuel.

Final thoughts

We don't think making your own DEF solution is a good idea. It comes with a lot of things you need to know how to do and a lot of obstacles. Also, you will spend quite a lot of money on components and may not be able to mix them correctly to form good DEF. Bad fluid will not be accepted by modern vehicles that have all forms of sensors that check the quality of the fluid and its chemical composition.

Also, don't consider buying cheap DEF that comes without any certificates and with unknown origin. We can assure you such products will never do anything good to your vehicle or equipment. It's not extremely expensive to refill your DEF tank every time you buy diesel fuel - it will just cost you a couple of dollars each time. But this will help you save your vehicle from damage and also make sure your car reduces its impact on the environment.