DEF Holding tank

[jpnj2]

I have a 2013 Thor Tuscany 36 xte the tank is black. No way to see inside to check the def level. The def level in the dash panel shows 4 solid green bars after filling the fuel tank, I added“three gal.of def, so I’m thinking the dash guage is B/O

[RWF]

We have a 14 Tuscany 36 and have had an issue a couple times where the computer thought the DEF had run out but there was actually plenty. So far we have solved it by just keeping it full. Any time the dash lights show 3/4, I put more in. The lights seem to be accurate until the computer messes up then it goes back and forth between the actual level and empty. Mine has a guage on the tank also that seems to be accurate, but the key has to be on to register properly.

[RWF]

You do know that the DEF guage has nothing to do with the fuel level.

[GVP-The Boxcar Children]

Originally Posted by RWF

We have a 14 Tuscany 36 and have had an issue a couple times where the computer thought the DEF had run out but there was actually plenty. So far we have solved it by just keeping it full. Any time the dash lights show 3/4, I put more in. The lights seem to be accurate until the computer messes up then it goes back and forth between the actual level and empty. Mine has a guage on the tank also that seems to be accurate, but the key has to be on to register properly.

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

[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...

[TurnerFam]

what I've found on our 4-Green Bar indicator on the dash, as compared to the more DETAILED gauge ON the DEF tank, itself, is this:

4 bars is full, of course
3 bars only means that you are only SLIGHTLY less than absolutely full
2 bars mean that you have MORE than 1/2 a tank full
1 bar means that you have MORE than 1/4 a tank full
1 ORANGE bar means that you are slightly LESS than 1/4 tank
1 RED bar/or blinking red bar means that you are LESS than 1/8 tank, and close to 'turtle mode' if not added to very soon.

I've also had my 'engine light' alert come on several times over the course of 5 years and over 100,000 miles, yet it was never anything of 'concern', but wound up being only that the DEF was 'low', maybe because the float level was being moved around by travel movement, yet was never in the Orange or Red level bar, OR that the DEF had recently been filled and it's possible that some 'dried' DEF particles fell into the tank during filling, when using an 'older' flexible fill tube, which I use in combination with the fill tube that comes with the 2 1/2 gal DEF jug, in order to best 'reach' the DEF fill outlet on the coach.
These lights always went away after 'so many miles' or 'a few more engine starting'...which I understand is typical of some of these 'alerts'...

[TurnerFam]

per FREIGHTLINER:

Fuel/DEF Gauge
The fuel and DEF levels are measured in a multipurpose fuel/DEF/voltmeter gauge. See Fig. 7.9 .

A. 1 to 4 lamps steady green in DEF lightbar, DEF level indicators.
B. 1 lamp steady amber in DEF lightbar, DEF low, refill DEF.
C. 1 lamp flashing red in DEF lightbar, DEF empty, refill DEF.
Fig. 7.9, Fuel/DEF/Voltmeter Gauge
Fuel level is indicated at the top of the gauge. Below the fuel level, a low fuel warning lamp illuminates amber when the fuel level drops below 1/8th of the capacity.
The DEF lightbar indicates the level in the DEF tank as follows.
Four bars illuminated green—Between 75% and 100% full
Three bars illuminated green—Between 50% and 75% full
Two bars illuminated green—Between 25% and 50% full
One bar illuminated green—Between approximately 10% and 25% full
One bar illuminated amber—DEF low, refill DEF
One bar flashing red—DEF empty, refill DEF

[RWF]

When my DEF level gets down near 1/2, the fuel guage goes to 0, red lights flash and warning horn goes off. (Very irritating). If I keep it full, no problem. It must be an issue with the DEF level sensor.........

[TurnerFam]

why they're not able to simply provide the same exact 'gauge' on the dash that is on the DEF tank itself is beyond me... sure would be simpler.

[jpnj2]

Originally Posted by RWF

You do know that the DEF guage has nothing to do with the fuel level.

Of course

[jpnj2]

Originally Posted by TurnerFam

what I've found on our 4-Green Bar indicator on the dash, as compared to the more DETAILED gauge ON the DEF tank, itself, is this:

4 bars is full, of course
3 bars only means that you are only SLIGHTLY less than absolutely full
2 bars mean that you have MORE than 1/2 a tank full
1 bar means that you have MORE than 1/4 a tank full
1 ORANGE bar means that you are slightly LESS than 1/4 tank
1 RED bar/or blinking red bar means that you are LESS than 1/8 tank, and close to 'turtle mode' if not added to very soon.

I've also had my 'engine light' alert come on several times over the course of 5 years and over 100,000 miles, yet it was never anything of 'concern', but wound up being only that the DEF was 'low', maybe because the float level was being moved around by travel movement, yet was never in the Orange or Red level bar, OR that the DEF had recently been filled and it's possible that some 'dried' DEF particles fell into the tank during filling, when using an 'older' flexible fill tube, which I use in combination with the fill tube that comes with the 2 1/2 gal DEF jug, in order to best 'reach' the DEF fill outlet on the coach.
These lights always went away after 'so many miles' or 'a few more engine starting'...which I understand is typical of some of these 'alerts'...

I really appreciate all of the replies. I was told by the dealership, to fill the def tank after issuing 3 tanks of diesel fuel. I wanted to Know how many gallons does the def tank hold. Good forum guys this is the place to be if you you Are a newbie like myself

[EA37TS]

My rig supposedly has a 13 gallon def tank. On our last trip the def indicator got down to 1 green bar. About 75 miles later I filled the tank and added 5 gallons of def ( 2 2.5 gallon jugs) and all four indicators are green again.

I do not have a gauge on the def tank, at least not one that can be seen because of the Super C's step moulding that surrounds the tank.

[jpnj2]

Originally Posted by EA37TS

My rig supposedly has a 13 gallon def tank. On our last trip the def indicator got down to 1 green bar. About 75 miles later I filled the tank and added 5 gallons of def ( 2 2.5 gallon jugs) and all four indicators are green again.



I do not have a gauge on the def tank, at least not one that can be seen because of the Super C's step moulding that surrounds the tank.

Thanks,this the info I was looking for 13 gal tank now I can store a few gal in my storage bay

[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.

[GVP-The Boxcar Children]

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...

Funny guy you are, Bob! I used to do exactly that with the fuel tank in my '57 Chevy pickup!
GVP

[Bob Denman]

Originally Posted by GVP-The Boxcar Children

Funny guy you are, Bob! I used to do exactly that with the fuel tank in my '57 Chevy pickup!
GVP

It's siomple, fool-proof, and you've always got a marshmallow stick handy!

My Grampa Denman kept one that he used in his last Model-T. It was out in his workshop. I'll never admit to anything; but it also made a pretty handy switch!

[engrprof]

Originally Posted by RWF

We have a 14 Tuscany 36 and have had an issue a couple times where the computer thought the DEF had run out but there was actually plenty. So far we have solved it by just keeping it full. Any time the dash lights show 3/4, I put more in. The lights seem to be accurate until the computer messes up then it goes back and forth between the actual level and empty. Mine has a guage on the tank also that seems to be accurate, but the key has to be on to register properly.

On our 2019 Thor Aria the gage on the DEF tank keeps registering the level before the ignition key was turned off. When I'm filling with DEF I leave the ignition key ON.

[frankgtx]

Older MB Sprinter models do not have a DEF gauge. There’s no way to dipstick the DEF level. If you run out of DEF on a Sprinter you will get a warning advising of x number of starts. If you ignore the warnings you will be shut down permanently to avoid damage to the emission control system. Adding DEF once that occurs will not help. You will need to have the vehicle towed or have a MB mechanic reset the emissions control system in order to restart the vehicle. I know the DEF tank capacity. I know the DEF consumption. I maintain a log. Also DEF is basically water and urea. Water evaporates. Urea concentration increases which can cause damage to emissions system. Diesel pick-ups get a lot of use so DEF does not sit in reservoirs for a long time. Motor homes are not driven as regularly. Do not purchase large quantities of DEF ahead of time. Best to keep refilling vehicle reservoir with fresh stuff regularly than letting it sit in hot weather for months (plastic reservoirs with plastic caps are not air tight and evaporation will occur). Note that DEF suppliers do not post date produced info on their containers. Guess why? Also, when you buy DEF the area around the bottle cap maybe covered in white crystals. That is the urea after the water has evaporated. Another great government regulation to make greenies happy. There is a way to disconnect the emissions control system on all diesel/def vehicles. Although Texas does not test emissions for tag renewals on diesels it’s illegal to disengage emissions control. You can be cited if authorities note excessive emissions from your vehicle plus disengaging might create issues if you ever plan on selling your motor home.

[knucklehead]

Originally Posted by Bob Denman

It's siomple, fool-proof, and you've always got a marshmallow stick handy!

My Grampa Denman kept one that he used in his last Model-T. It was out in his workshop. I'll never admit to anything; but it also made a pretty handy switch!

What the hell does DEF stand for????

[EA37TS]

Originally Posted by knucklehead

What the hell does DEF stand for????

Diesel Exhaust Fluid