DEF fluid - Shelf life?

I have a jug of the stuff I bought about 1.5 years ago. Does it go bad? Or just go ahead and use it?

It says "012418B". Possibly manufactured in January of 2018?

That bottle contains urea and water.  No shelf life.  Lasts forever.

Matthew Kennedy said:

That bottle contains urea and water.  No shelf life.  Lasts forever.

That's not true at all.  DEF breaks down over time.  Shelf life is between 1 and 2 years depending on storage conditions.  The manufacturer's website will have specifics.

APEowner said:

Matthew Kennedy said:

That bottle contains urea and water.  No shelf life.  Lasts forever.

That's not true at all.  DEF breaks down over time.  Shelf life is between 1 and 2 years depending on storage conditions.  The manufacturer's website will have specifics.

It definitely breaks down, and storage temperature makes a big difference. Warm weather storage can cut the shelf life down to under 6 months.

carczar_84 said:

APEowner said:

Matthew Kennedy said:

That bottle contains urea and water.  No shelf life.  Lasts forever.

That's not true at all.  DEF breaks down over time.  Shelf life is between 1 and 2 years depending on storage conditions.  The manufacturer's website will have specifics.

It definitely breaks down, and storage temperature makes a big difference. Warm weather storage can cut the shelf life down to under 6 months.

Granted I know nothing about this, but don't most vehicles hold ~10k miles worth of fluid (I thought I read that somewhere, but I could be imagining things). So if you average 12k miles per year in the south, half the miles the DEF isn't doing it's job? 

I'm really just curious, no desire to own a diesel.

DEF usage varies dramatically with how the vehicle is being used.but I've never gotten anywhere near 10k miles to a tank in my RAM 3500.  It may be 5k unladen but I'd have to check my records to be sure.  I curious now.  I'll try and remember to grab the book out of the truck and update this thread.

This letter from Motorcraft to all Ford and Lincoln Dealers does a good job of explaining the subtleties of DEF storage and shelf life

March, 2018
To: All Ford and Lincoln Dealers
Subject: Reminder of Conditions affecting Diesel Exhaust Fluid (DEF) Shelf Life and Fluid Quality
Diesel Exhaust Fluid (DEF) has been required for the 2011 MY and forward diesel vehicles to meet 2010 EPA emission regulations.
DEF is a non-hazardous clear fluid (67% deionized water / 33% chemically pure Urea) that is injected into the diesel exhaust system to reduce NOx emissions.
The following communication provides guidelines on DEF and the proper storage levels to maintain the chemical concentrations advertised on the label.
DEF INVENTORY STORAGE LEVELS
• If a climate controlled facility is available, for maximum shelf life, store between 68oF (20oC) and 23 oF (-5oC).
• Store DEF out of direct sunlight. If DEF is stored outside it must be shaded from the sun.
• DEF will freeze below 12oF (-11oC). Do not store outside or in a facility where the temperature will drop below 23oF (-5oC)
• Store DEF below 86oF (30oC), if possible and/or in the coolest part of the storage facility. If storing DEF below 86 oF (30oC) is not feasible, the inventory needs to be managed accordingly.
• Shelf life should be based on the period of time past the date code on the bottle. The date code is formatted as MMDDYY (i.e. 022817 = February 28, 2017).
• The issue with selling DEF that is beyond its shelf life is the possibility of selling the customer a product that does not meet what is advertised on the label.
• DO NOT PURCHASE MORE PRODUCT THAN WILL REMAIN IN INVENTORY BEYOND THE SHELF LIFE SHOWN IN THE BELOW CHART, IF AVERAGE DAILY TEMPERATURES WILL CONTINUALLY EXCEED THOSE SHOWN IN THE CHART BELOW.
• UNDER NO CIRCUMSTANCES SHOULD DEF BE KEPT FOR MORE THAN 3 YEARS.
The table below shows shelf life for DEF continuously exposed to these temperatures for the entire period. Cycles where the maximum daily temperature is similar to what is shown below, will have longer shelf life than shown. Shelf life for product in inventory should be based on the average daily temperature not the day's maximum temperature.

DEF Shelf Life versus Temperature

Constant Ambient Storage          Shelf Life
Temperature                                    In Months
≤50 °F (10°C)---------------------36
<77 °F (25°C)---------------------18
≤86 °F (30°C)---------------------12
≤95 °F (35°C)---------------------6
<104°F (40°C)---------------------2

EXAMPLE: Typically, two hottest months in Phoenix Arizona are July and August. The average temperature for these months can typically be 95oF (35oC), according to the data from the National Weather Service. The average daily temperatures for these months ranged from 104oF (40oC) to 85oF
(29oC), while for some days daily highs can reach 115oF (46oC). For areas that see these average temperatures DEF shelf life would be 6 months.
DISPENSING NOZZLE
• Available for Motorcraft DEF is a nozzle that will allow the operator to add DEF to the tank while minimizing contamination, spilling and over filling.
• Nozzles can be reused but should be properly stored between fillings. Nozzles come in a resealable plastic bag and should be rinsed with clean water before being stored in it’s re-sealable plastic bag.
• The DEF nozzle should not be used for other chemicals, like oil, coolant, etc.
• Do not use nozzles or funnels that have been used to other chemicals
VEHICLES CONTAINING DEF
DEF in a vehicle is still acceptable for vehicle consumption even if the vehicle has been exposed to temperatures above 86 oF (30oC). For the same reasons stated above, at these temperatures, urea concentration will remain reasonably stable.
• DEF in vehicles is susceptible to the same degradation as in containers.
• The SCR (selective catalytic reduction) system has been calibrated to function properly with urea concentrations different than 32%. The only consequence of operating with a urea concentration less than 32% is faster consumption.
• DEF that has degraded beyond the point for the calibration to compensate will set off a warning on the instrument panel (refer to the owner guide).
• Unless there is a warning light on the instrument panel there is no reason to consider draining the DEF from the tank simply due to age of the DEF. However, it is highly unlikely the warning would be caused by aged DEF and normal diagnostics should be followed.
• DEF freezing in the vehicle tank will not cause any problems as long as the tank is not over filled. The vehicle is equipped with a heater to thaw frozen DEF when the vehicle is started and then the system will function normally.
LARGE CONTAINERS OF DEF
Large containers, 55 gallon drums and 275 gallon totes are affected by temperature the same as described above for containers. Shelf life should be estimated using the temperature chart. Due to the mass of fluid, the temperature fluctuations may not be as great as smaller containers.
• Refilling of Motorcraft drums and totes is not an acceptable practice and bulk DEF is not available from Motorcraft
• Fluid in drums and totes are more susceptible to contamination since at times the container will be open to the atmosphere as dispensing equipment will be removed and installed
• Minimize the time the bung hole is left open
• Be sure the dispensing equipment is clean before inserting it into the drum or tote
DEF DISPENSING EQUIPMENT FOR LARGE CONTAINERS
Use the proper dispensing equipment that is specifically made for DEF.
• Dispensing equipment must be made of stainless steel or plastic compatible with urea (ie, polyethylene, polypropylene, etc. See ISO22241-3).
• DEF is corrosive to most metals.
• The use of dispensing equipment made of materials incompatible with DEF, like used for coolant or oil dispensing equipment, will corrode and contaminate the DEF and the equipment will eventually malfunction.
• DEF Dispensing equipment is available through Rotunda (order on the web through https://rotunda.service-solutions.com/en-US/Pages/home.aspx, https://www.rotundatechtools.com/rotunda/ or by calling 1-800-ROTUNDA and select option #2).
QUESTIONS
For questions, please contact your Aftermarket Zone Manager or Robert Boss (rboss@ford.com).

z31maniac said:

Granted I know nothing about this, but don't most vehicles hold ~10k miles worth of fluid (I thought I read that somewhere, but I could be imagining things). So if you average 12k miles per year in the south, half the miles the DEF isn't doing it's job? 

I'm really just curious, no desire to own a diesel.

I think that was a claim from VW during the DieselGate era. Lots of people were skeptical at the time, and of course we now know that they achieved that claim by barely using any DEF and allowing ridiculous NOx emissions.

The answer in the real world varies a ton depending on specific vehicles and usage but nobody that I'm aware of is getting anything close to 10k miles between DEF refills. In a passenger vehicle it's usually filled once every 3-4 tanks of fuel. In a semi truck, DEF consumption is often around 3-5% of diesel fuel consumption, so 100 gal diesel would use 3-5 gal of DEF. DEF consumption is a metric that trucking fleets consider when purchasing just like fuel or oil consumption. So trucking OEMs are always working to decrease DEF consumption just like they do oil consumption of fuel consumption. There's a balance to all of it, and you can't usually improve one area without impacting another.

10K miles is the approximate DEF interval on our TDI Golf, it's fully compliant with both stages of the EPA mandated "fixes" done and no modifications other than better tires.

There's a heater in the DEF tank to keep it from freezing, not sure if it heats with the engine off though, I wouldn't think so.

I had to have the heater circuit and DEF injection line replaced, don't know if the issues were related, but the failed heater caused a CEL, and the leak caused a stalagtite of DEF crystals to build up on the side of the engine's head. All repairs were covered under the extended emissions warranty.

I found it interesting that it freezes below 12F. Seems like it could be a problem for owners in northern regions  

So does that mean the DEF system isn't functioning when the outside temp drops below 12F? Or do the have heaters on the vehicle tanks?

In reply to No Time :

Read the post above yours.

In reply to z31maniac :

I just know that number from the DEF we keep on site. The building regularly sees temps in the 80's through summer (N. Cal) and the vendor data sheets specify a shelf live of approximately 6-8 months at those temps.  It caught me off guard when we read it the first time too.

Thanks guys. Sounds like its probably best to go and buy new one. 

Just as a reference, the car holds 2.5 gallons and I think I can get 20k miles out of that. The car will usually do 500 miles to a tank of diesel, so 20 tanks?

Not sure if BMW is also cheating and only injecting it while someone is watching, but no way its 3-4 tanks. 

As noted above, DEF usage varies widely by vehicle and usage.

My RAM 3500 dually used a gallon of DEF this weekend to go 600 miles... with 4500lbs of camper in the bed, and 7000lbs of trailer behind.  Running empty, it lasts a lot longer.

Due to shelf life and other variables, I try to only fill my DEF tank when prepping for a trip where we are towing.  Otherwise I keep it ~1/2 full, so it's getting cycled through more often.  FCA has been known to blame DEF system problems on the fluid to avoid warranty repairs, so I keep receipts and records of lot #s, and I try to only put in the freshest fluid I can find.  

In reply to Rodan :

How do you know if the fluid is fresh? I was thinking of picking it up at the turnpike gas station. 

I'll check to see if it has any dates when I pick it up. 

Also the reason I have this is because I thought I would use much more ... but the car barely uses any. 

In reply to Slippery (Forum Supporter) :

I use Peak BlueDEF because they put a lot number that has a date code on the packaging.  Other brands may do the same, I'm not sure.  The Peak has proven to be pretty universally available everywhere I've been.

Bought this guy:

Found this online:

In case anyone has the same problem. 

Now I have to figure out what to do with the old DEF. 

In reply to bigdaddylee82 :

I think I type slow and missed your response. 

I run my DEF down to 10% before adding, then it's only one container of Blue DEF, never top off the tank. FLAPS has the best born on dates as I've seen. Trucks stops or high volume convenience store fuel stations may have fresher also. Never had an issue.

Always check the date.

This has to be a canoe bringing this back up.

bigdaddylee82 said:

10K miles is the approximate DEF interval on our TDI Golf, it's fully compliant with both stages of the EPA mandated "fixes" done and no modifications other than better tires.

There's a heater in the DEF tank to keep it from freezing, not sure if it heats with the engine off though, I wouldn't think so.

I had to have the heater circuit and DEF injection line replaced, don't know if the issues were related, but the failed heater caused a CEL, and the leak caused a stalagtite of DEF crystals to build up on the side of the engine's head. All repairs were covered under the extended emissions warranty.

They heat the DEF all the time.  You can find the DEF tank with a heat gun in the winter.