DEF Holding tank

[TurnerFam]

it won't matter if you don't have a diesel...

if you do, it's a simple liquid that you pour into a separate 'tank'... easy, and it doesn't use much at all - it's not like diesel fuel - but more like a 'cleaner' to make the exhaust less 'smoke/smog', and more like water droplets...

[EA37TS]

Originally Posted by frankgtx

... Note that DEF suppliers do not post date produced info on their containers. ...

Quality Def does have a date of expiration. On Blue Def they list the year and then the number of days to years end (Reverse Julian Calendar). For example a bottom with the date 20001 expires on December 31, 2020. Subtract 1 from the year and it will be the year of manufacture. A bottle with 21364 will expire on January 2, 2021 (give or take a day). DEF can last up to 2 years is stored in ideal conditions. Unfortunately due to temp extremes the storage compartments on an RV are not ideal conditions unless they are climate controlled (heat and AC).

If you do a google search there is a ton of info on how to read the date codes on DEF bottles.

Basically this year you should be buying DEF with 20 or 21 in positions 3 and 4 of the code and the lowest number possible in positions 4, 5 and 6.

The date structure is part of the API Certification instructions for DEF.

[Slickrick racer]

Originally Posted by EA37TS

Somewhere I read where the average DEF consumption is 3 percent per gallon of fuel or 3 gallons of DEF to 100 gallons of fuel. Based my DEF and Fuel consumption since we bought this coach I'd say that is pretty darn close if not right on the money. A couple more 800 to 1000 mile trips and I will have a better handle on the overall DEF usage.

That would be one heck of consumption rate. I used less than 5 gallons on a 3700 mile trip in my Palazzo.

[Slickrick racer]

Originally Posted by EA37TS

Somewhere I read where the average DEF consumption is 3 percent per gallon of fuel or 3 gallons of DEF to 100 gallons of fuel. Based my DEF and Fuel consumption since we bought this coach I'd say that is pretty darn close if not right on the money. A couple more 800 to 1000 mile trips and I will have a better handle on the overall DEF usage.

That would be one heck of consumption rate. I used less than 5 gallons of DEF on a 3700 mile trip in my Palazzo.

[EA37TS]

FWIW

Cummins says average consumption is approx 2 percent.


DEF Q and A.pdf

[campergal]

Hi All, we completed our maiden voyage down the west coast with our 2011 Thor 23S Freedom Elite. We have an "old" opened (we don't know how many years its been stored) carton of DEF in our storage compartment. We were fearing that we would be notified somewhere on the dash about needing DEF. Our DEF tank is on the lower side of our RV with the large plastic tank cap installed above the opening of the side door so......you would be pouring uphill to get the DEF in?!? Also, there is no way to see the level of DEF in the tank. Please, we need to tap into the experience on this forum! Thanks much

[paulwadley]

Does the cap say DEF on it? Also you might want to read the date code on the stored DEF you have to be sure it is still usable. There is a self life on it. You can look on the internet to see how to read the code for the actual date it was manufactured. If that cap is where you pour the DEF in it, you should be fine just pouring it into it as long as it is the DEF tank filler and not the diesel fuel filler. When I had our MB Sprinter chassis Class C, my DEF tank was located under the hood with a DEF cap on the tank.

Paul

[simidrm]

Originally Posted by Bob Denman

Why not ue an old Modle T fuel tank gauge?

You pick up a clean straight stick that is long enough to reach to the bottom of the tank...

I would be very careful using a stick, the bottom of the def tank has a rubber bladder

[Dan-sr@perra-us.net]

Originally Posted by campergal

Hi All, we completed our maiden voyage down the west coast with our 2011 Thor 23S Freedom Elite. We have an "old" opened (we don't know how many years its been stored) carton of DEF in our storage compartment. We were fearing that we would be notified somewhere on the dash about needing DEF. Our DEF tank is on the lower side of our RV with the large plastic tank cap installed above the opening of the side door so......you would be pouring uphill to get the DEF in?!? Also, there is no way to see the level of DEF in the tank. Please, we need to tap into the experience on this forum! Thanks much

If you do not know how old just discard and buy new. Average def consumption is reported to be 1% to 3% of the diesel fuel burned until you can determine your usage you should estimate 1 gallon of DEF for every 50 gallons of fuel burned. So, if you have a 10-gallon DEF tank you should probably top up the DEF Tank after 250 gallons of fuel If you get 10mpg the would be about once every 2500 miles.

Def is non-toxic and consists of deionized water and urea. Urea is a component of agricultural fertilizer. It should be safe to dump but to be sure you do not violate any Hazardous waste disposal regulations contact your local trash disposal organization about how they want it handled.

[simidrm]

Originally Posted by GVP-The Boxcar Children

Interesting that the key has to be on to read the DEF level at the tank. I thought that was odd, too, as our Aria is the same way. I'm considering running a hot wire and toggle switch to the compartment so I can just flip the switch at the tank to check, then flip it off. That would be most handy, as we seem to use a lot of DEF on our trips even though those round-trips total less than 1,000 miles.
GVP

That might not be a good idea,the def system uses a multiplexed wiring and there are 3 sensors in the tank you have a level sensor,def quality sensor, and a temp sensor so if you shut the power off to the tank you will get def fault codes resulting in a derate, most common problems are because the tanks are left partially full and the def dries and becomes crusty which keeps the level float from reading correct, but by keeping system full especially when parked will keep the floats from hanging up, and you just can’t replace the float you have to replace the header as a assembly which isn’t cheap .

[simidrm]

Originally Posted by EA37TS

Somewhere I read where the average DEF consumption is 3 percent per gallon of fuel or 3 gallons of DEF to 100 gallons of fuel. Based my DEF and Fuel consumption since we bought this coach I'd say that is pretty darn close if not right on the money. A couple more 800 to 1000 mile trips and I will have a better handle on the overall DEF usage.

It is supposed to use 2% of what you use in fuel, and that is under ideal conditions, but towing and an aging system will consume more, def consumption is based on the nox sensors and there are set to reduce nox levels by 80% of what the inlet nox sensor reads but as these sensors age and they tend to read less accurate you consume more def, replacing them is fairly easy but really expensive, but I carry a def refractor to test all def fluid before it goes into the tank, get them on Amazon for around 20.00 and twice at a truck stop I got def that was a lower urea concentration that allowed, most is 34% urea and minimum is 32%