Help! Advice on DEF

[Rodgers]

I have been using DEF in my 2014 since I bought it. DEF isn't caustic in any way, shape or form! If you should happen to spill some all you will see is a white residue. That can be washed off with water, no soap needed. If your's is like many others no matter what brand. It will warn you before it runs out. And may slow your speed down to what will seem like a crawl. Don't be afraid of DEF fluid!

[SlowrideHD]

Correct Mr. Rodgers! DEF is not caustic...if it was, many of our internal organs would be in serious trouble. Urea, when dissolved in water is neither acidic or basic. As far as storage, you do not generally want it to be left in an open container. While it will freeze at 12F (-11C), the freezing and thawing of the 32.5% DEF does not degrade the mixture at all. The DEF tank in your vehicle will have a heater built in so that the tiny bit that is injected into your SCR system is thawed.

Big Brother has decreed that the NOX emissions from our diesel exhaust may be somewhat minimized by the addition of DEF. The ammonia produced by the hydrolysis of the urea reacts with the nitrogen oxide emissions and is converted into nitrogen and water within the catalytic converter. Of course our NOX would not be as high if they didn't mandate that a portion of the dirty exhaust was recirculated back into the clean intake air (which must be first cooled down within the EGR cooler). Also they have decided to severely restrict the exhaust flow with a particulate filter that has passages that are so tiny that they trap soot particles (which then must be burned away every few hundred miles) by wastefully injecting good diesel fuel right into the exhaust stream which ignites and creates an 1150F blowtorch that travels down the exhaust pipe and burns away the accumulated soot.
Aren't you glad you have a diesel now? HaHa

[waybeck2018]

I would caution any DEF user to make sure that the product purchased meets ISO 22241 specification. I purchase only the main known brand or one auto parts store has their name brand that meets the specification. Blue Def can be bought in many places and O'Riley sells both Blue Def as well as their name brand. Again, both meet the stated specification and it is clearly listed on the container. DO NOT buy Walmart brand at about half price. Cheap is not the way to go here.

[Larry-NC]

Originally Posted by rlh1957

The DEF is the governments answer to cleaner burning diesel... add some unknown cat piss smelling crap in a 3 - 6 gallon tank and make the test show better emissions to keep the tree huggers happy.

I don't own a diesel and never have. My only experience with a Diesel involves a 32' U-Haul box truck trip from Philly to Raleigh in 2001. But I was curious about this stuff they dump in the exhaust system.

Here is a link to the Material Safety Data Sheet (MSDS) for Peak's Blue DEF product. The MSDS includes the chemical composition. It is quite straightforward. Blue DEF is 67.5% water and 32.5% urea.

The MSDS also states:
2. Exposure controls
Personal protective equipment : Avoid all unnecessary exposure. Gloves. Protective goggles.
and
7.1. Precautions for safe handling
Precautions for safe handling : Wash hands and other exposed areas with mild soap and water before eating, drinking or
smoking and when leaving work. Provide good ventilation in process area to prevent formation
of vapor.

Following are extracts from the Wikipedia article on Urea.

Urea is highly soluble in water. (I wonder if you could re-dissolve the crystallized urea in water and use it. You might need a hygrometer to get the dilution right.)

Many animals (e.g., dogs) have a much more concentrated urine and it contains a higher urea amount than normal human urine; this can prove dangerous as a source of liquids for consumption in a life-threatening situation (such as in a desert).
(This is where the cat piss comment comes from.)

Urea is used in SNCR and SCR reactions to reduce the NOx pollutants in exhaust gases from combustion from Diesel, dual fuel, and lean-burn natural gas engines. The BlueTec system, for example, injects a water-based urea solution into the exhaust system. The ammonia produced by the hydrolysis of the urea reacts with the nitrogen oxide emissions and is converted into nitrogen and water within the catalytic converter. Trucks and cars using these catalytic converters need to carry a supply of diesel exhaust fluid, a solution of urea in water.

Larry

[doc73]

Originally Posted by waybeck2018

I would caution any DEF user to make sure that the product purchased meets ISO 22241 specification. I purchase only the main known brand or one auto parts store has their name brand that meets the specification. Blue Def can be bought in many places and O'Riley sells both Blue Def as well as their name brand. Again, both meet the stated specification and it is clearly listed on the container. DO NOT buy Walmart brand at about half price. Cheap is not the way to go here.

80k miles on the cheap stuff.. Still going just fine.

I misspoke about the usage, it. Was based on the amount of fuel used, not milage (mpg changes on load).

Everyone else covered the storage and shelf life. It is mostly water and will freeze.

[SlowrideHD]

Originally Posted by waybeck2018

I would caution any DEF user to make sure that the product purchased meets ISO 22241 specification.
Again, both meet the stated specification and it is clearly listed on the container. DO NOT buy Walmart brand at about half price. Cheap is not the way to go here.

Curious. What information do you have about the Walmart DEF (assume you mean the SuperTech brand) that it is not suitable? Or is there something else?

IF a product does not adhere to the ISO 22241 standards, then that fluid cannot by definition be called a Diesel Exhaust Fluid (DEF).

[doc73]

Originally Posted by SlowrideHD

Curious. What information do you have about the Walmart DEF (assume you mean the SuperTech brand) that it is not suitable? Or is there something else?



IF a product does not adhere to the ISO 22241 standards, then that fluid cannot by definition be called a Diesel Exhaust Fluid (DEF).

Yep 80k miles of Walmart Def and truck stop Def (which is the other one EVERYONE seems to swear will destroy the truck. Guess I like to live on the edge..

[Go UK]

The MB has so many lights, I suggest reading the manual.

[rmoore0852]

Originally Posted by vettecrazy

Thank you, so just look for the light. We should have been told this with this being our first diesel. I guess we have a spot that you fill it, we are aiting for a call from the service manager for education,

Yes, there is a separate fill point for the DEF. It is usually a blue cap somewhere. I know nothing about the MB so can't help you with where it is or even be sure that it is a blue cap.


Very glad that you asked, and shame on your dealer for not showing it to you. I have seen MANY pickups towed into the shop with very expensive damage, due to an unknowing person thinking that it was just a fuel additive. Seen several times that somebody who didn't know any better just dumped it into the fuel tank. That's a very expensive mistake.

[herbike]

DEF fluid is not caustic but it is corrosive. It is mainly liquified urea fertilizer. Here in the northwest it is manufactured by the same company that makes dry urea fertilizer, ammonia nitrate and explosives for the mining industry. Dyno Nobel is the company, they have plants in Utah and other parts of the country.
Here is their statement of the make up of DEF.
https://www.dynonobel.com/~/media/Fi...20Solution.pdf

[TryingToLearn]

Dealer told us to add some every 3rd tank. Dealer had no clue.

When the DEF warning light comes on we added 2 1/2 gallons without a problem. Purchased Blue DEF box at Walmart. Warning light looks almost like a campfire over water to me.

[FFred]

I much prefer to fill the DEF tank underway as needed , every3 or 4 tanks of fuel or so, to keep the stuff from drying out.


On the completion of a trip we fill the tank really full for while its just sitting.

[koller1509]

Unless you are really pulling a load, def usage is probably somewhere around 1000 miles per gallon or more. If you are towing heavy it will drop to 300-500 miles per gallon. FYI these figures are from a 3500 dually and a 16000 pound fifth wheel.

[grumpyoldman]

As some others have stated correctly, DEF usage is based on gallons of fuel used and not miles driven. I have been tracking my usage since I bought my truck and it comes to 1.33% of fuel used. (About 13 gallons a year for me). Of course this means more used when towing and less used when not towing.
I wait until my level is around 5% before filling up and I could go another 500 miles, so there is NO need to carry a spare bottle of DEF. Surely you can find DEF in the next 500 miles.
My first year of ownership I purchased DEF at Walmart. Once I found out that it is available at truck stops, I fill up there exclusively.

FYI: Oil refineries have been mandated by the EPA since 2005 (if I remember correctly) to treat the exhaust of all FCC (fluid catalytic cracker) units with ammonia to reduce NOX emissions. Same as on diesel trucks except on a much grander scale. 19% liquid ammonia injected into an SCR the size of a 2 story house. Used 3000 gallons a day of this solution to keep the NOX below the EPA limit.

[tomkatb]

We get about 1000 miles per gallon of def not towing. Cummins diesel.

About 200 miles per gallon towing a #14,000 fifth wheel.

Def is much cheaper at truck stops. About 50%.

If I were you I would travel with a jug of it in the rv. Fill when the light comes on.

The fluid has a shelf life. We store ours indoors when not traveling.

[Brewhedd]

I don't use cheap DEF. IMO these trucks are too expensive to worry about saving a few bucks. You can find 4- 2 1/2 gallon jugs of Valvoline DEF on Ebay for a pretty good price.

[koller1509]

Originally Posted by grumpyoldman

As some others have stated correctly, DEF usage is based on gallons of fuel used and not miles driven. I have been tracking my usage since I bought my truck and it comes to 1.33% of fuel used. (About 13 gallons a year for me). Of course this means more used when towing and less used when not towing.
I wait until my level is around 5% before filling up and I could go another 500 miles, so there is NO need to carry a spare bottle of DEF. Surely you can find DEF in the next 500 miles.
My first year of ownership I purchased DEF at Walmart. Once I found out that it is available at truck stops, I fill up there exclusively.

FYI: Oil refineries have been mandated by the EPA since 2005 (if I remember correctly) to treat the exhaust of all FCC (fluid catalytic cracker) units with ammonia to reduce NOX emissions. Same as on diesel trucks except on a much grander scale. 19% liquid ammonia injected into an SCR the size of a 2 story house. Used 3000 gallons a day of this solution to keep the NOX below the EPA limit.

There are many of us that base our usage on miles instead of gallons of fuel, it works the same. The heavier the load the more DEF used per gallon of fuel and less miles per gallon of DEF. You are the first person I have heard use a percentage. Using your percentage I am at 3.2% towing and 1.8% when not. I use about 30 gallons per year- about 7000 miles towing heavy and 5000 empty.

[doc73]

I wish I could find the thread, it might not even have been here. But the person found some documentation about the correlation of fuel burned to the amount of Def injected.

I. Get about 5 to 6k per 5 gallons of Def in my chevy. I tow about 1/4 to 1/2 my trucks miles.

[olemax]

Originally Posted by koller1509

Best to store it at room temperature, Being stored at high temperatures shortens its shelf life.

I have a some advice, after learning the hard (expensive) way having to replace the pump and injector on a recently purchased used truck that sat a long period in summer heat.

Buying DEF: Buy from a place that sells a lot of it (turnover means fresh). It should be ISO 2224 and/or API certified. The containers are (or should be dated). The shelf life of DEF is a function of ambient storage temperature. DEF will degrade over time depending on temperature and exposure to sun light. Expectations for shelf life as defined by ISO Spec 22241-3 are the minimum expectations for shelf life when stored at constant temperatures. If stored between 10 and 90 deg F, shelf life will easily be one year. If the maximum temperature does not exceed approximately 75 deg F for an extended period of time, the shelf life will be two years. Don't leave the vehicle sitting for an extended period with DEF in the tank. Here's the rest of the article on DEF from a supplier. https://www.jmesales.com/commonly-as...ust-fluid-def/

I hope this saves someone a lot of grief and $$!.
Happy Camping,
Olemax

[Ratchethead]

Originally Posted by vettecrazy

We have the FR Sprinter, will turn 1,000 miles soon, we we’re just told by a owner of a Mercedes about the DEF, we have never added any. Think we have done harm?

Diesels have not always used DEF, it depends on the year, diesels that use it have gauge on the dash. Earlier versions used diesel fuel itself and an EGR valve to do what newer engines do with DEF.