# Lesson Learned: Top off DEF before driving >300 miles



## JohnARM (Dec 19, 2017)

300 miles is not enough warning?


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## Taxman (Aug 10, 2017)

JohnARM said:


> 300 miles is not enough warning?


When fuel stops are more than 300 miles apart, yes. 

But I thought it would say "35% full" before it would say "300 miles remaining".


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## boraz (Aug 29, 2013)

Taxman said:


> When fuel stops are more than 300 miles apart, yes.
> 
> But I thought it would say "35% full" before it would say "300 miles remaining".


not according to the owners manual


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## obermd (Mar 3, 2012)

I would think the real lesson learned here is to know how to top off the DEF before you go on any road trip or expect bad weather.


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## JohnARM (Dec 19, 2017)

Taxman said:


> When fuel stops are more than 300 miles apart, yes.
> 
> But I thought it would say "35% full" before it would say "300 miles remaining".


The DEF tank does not need to be filled as often a the fuel tank. It is not like fuel will go 700 miles but DEF only 300. The opposite is the case.


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## JohnARM (Dec 19, 2017)

What is the capacity of the DEF tank?


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## Rivergoer (Mar 30, 2017)

JohnARM said:


> What is the capacity of the DEF tank?


Gen 1 DEF = 4.5 Gal (17.0 L)
Gen 2 DEF = 3.8 Gal (14.4 L)


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## JohnARM (Dec 19, 2017)

Rivergoer said:


> Gen 1 DEF = 4.5 Gal (17.0 L)
> Gen 2 DEF = 3.8 Gal (14.4 L)


Thanks! Mine will be a Gen 2.


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## HondaTech2016 (Apr 20, 2017)

Mine always tells me the percentage that is left, usually around 37%. Other than that it's says full. I bought the VW AdBlue off Amazon to get the cool unspillable bottle. It's only half gallon, so it would need to be refilled 4 times to get the 2.5 gallons in that the 37% indicates. Lot better than spilling it all over the side of your car lugging the 2.5 gallons jug around by that tiny hose.


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## Taxman (Aug 10, 2017)

JohnARM said:


> The DEF tank does not need to be filled as often a the fuel tank. It is not like fuel will go 700 miles but DEF only 300. The opposite is the case.


Right. 
So there's no reason not to tell the driver 'I need DEF in 1000 miles', so that the driver can include it in his next fuel stop.


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## obermd (Mar 3, 2012)

Taxman said:


> Right.
> So there's no reason not to tell the driver 'I need DEF in 1000 miles', so that the driver can include it in his next fuel stop.


Is DEF usage linear with respect to miles driven, or is it based on engine speeds and miles driven?


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## MRO1791 (Sep 2, 2016)

obermd said:


> Is DEF usage linear with respect to miles driven, or is it based on engine speeds and miles driven?


People generally say it's proportional to fuel use.. but knowing the kind of engine parameters that would require it, think excess air in the combustion process, with high pressure and temperature... That is what makes NOx, and DEF is injected into the exhaust to react in the SCR catalyst to scrub NOx from making it out the tail pipe.. so, think of conditions where those parameters might be met.. ironically lower engine loads, higher RPM etc.. so it's a bit more complicated to determine all the parameters that determine actual DEF consumption. 

Sent from my Moto G (4) using Tapatalk


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## JohnARM (Dec 19, 2017)

Taxman said:


> Right.
> So there's no reason not to tell the driver 'I need DEF in 1000 miles', so that the driver can include it in his next fuel stop.


Really? You need the car to tell you that? Just fill it every time you get fuel if that is the case. 300 miles of warning/driving range seems plenty - even in the Mohave Desert.

In fact, 1000 mile seems excessive to the point of being ignored - causing people to run out.


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## Taxman (Aug 10, 2017)

John, you're not getting my point. 
I'm saying if it's going to warn you, it should give warning in ample time so that you can take care of it without making a special stop just for the DEF. It should be programmed for driver convenience, not just to make the driver satisfy the car's needs. 

Since the logical way of dealing with the DEF is to include it in your next fuel stop, 300 miles isn't long enough if you don't plan on buying fuel in the next 300 miles. I don't want to be rushing home on December 26th and get a warning "fill DEF within 300 miles" when I'm 400 miles from home, had my final fuel and meal stop half an hour ago and have to drive to work tomorrow morning. That's just stupid software making my life more difficult.


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## JohnARM (Dec 19, 2017)

Taxman said:


> John, you're not getting my point.
> I'm saying if it's going to warn you, it should give warning in ample time so that you can take care of it without making a special stop just for the DEF. It should be programmed for driver convenience, not just to make the driver satisfy the car's needs.
> 
> Since the logical way of dealing with the DEF is to include it in your next fuel stop, 300 miles isn't long enough if you don't plan on buying fuel in the next 300 miles. I don't want to be rushing home on December 26th and get a warning "fill DEF within 300 miles" when I'm 400 miles from home, had my final fuel and meal stop half an hour ago and have to drive to work tomorrow morning. That's just stupid software making my life more difficult.


I understand. What I would prefer is a separate DEF "fuel gauge" with a warning light similar to what is used in a Class 8 truck. 

Alternatively, just fill it every time. I think that "too much" warning is also problematic is my point. My ex wife had a car that had a "low fuel light" at 8 gallons (20 gallon tank). She got to the point that she just ignored the light. Three times she ran it out of gas!

Programing to taste would certainly work for me also.


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## Taxman (Aug 10, 2017)

Ideally, I'd notice when it went from 100% to 37%, and plan to make my next fueling at a truck stop with DEF pumps. But I'd appreciate it if it would pop up on the display when it dropped below "full". Then I'd push the OK button to dismiss it, and try to remember to pump some DEF next week. 

Actually, in an ideal world, it would read 50% at half full instead of reading full, but that's another case where they put protecting the car from idiots ahead of making it convenient for knowledgeable drivers...


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## Rivergoer (Mar 30, 2017)

MRO1791 said:


> People generally say it's proportional to fuel use.. but knowing the kind of engine parameters that would require it, think excess air in the combustion process, with high pressure and temperature... That is what makes NOx, and DEF is injected into the exhaust to react in the SCR catalyst to scrub NOx from making it out the tail pipe.. so, think of conditions where those parameters might be met.. ironically lower engine loads, higher RPM etc.. so it's a bit more complicated to determine all the parameters that determine actual DEF consumption.
> 
> Sent from my Moto G (4) using Tapatalk


So DEF consumption is not limited solely to the regen cycle? 

This is my first DEF vehicle so I’m still learning. I always assumed regen was only time DEF is consumed.


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## MRO1791 (Sep 2, 2016)

Rivergoer said:


> So DEF consumption is not limited solely to the regen cycle?
> 
> This is my first DEF vehicle so I’m still learning. I always assumed regen was only time DEF is consumed.


No, from my research it is injected to react with the SCR catalyst and the reaction reduces NOx (though I don't think at all times, hence the NOx sensor before the SCR). The non-DEF LNT method (on my 2009 Cummins Bluetec) uses an absorption method (Lean NOx Trap). When that "trap" has absorbed all the NOx it can.. the Regen for the LNT (different from DPF regen) burns off the NOx using fuel in the exhaust stream. Since SCR uses no fuel for regen of the SCR, and uses small amounts of DEF.. the SCR technology has won the competition since it yields better MPG, and with less engine oil fuel dilution problems associated with post injection for the Regen events, now no diesels use the LNT emissions system. 

https://www.dieselforum.org/about-clean-diesel/what-is-scr

Also, the 2012 Jetta I had was LNT emissions.. and the "cheat" was a big contributor to the better MPG than it would otherwise not get with the proper LNT regens taking place.


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## Rivergoer (Mar 30, 2017)

MRO1791 said:


> No, from my research it is injected to react with the SCR catalyst and the reaction reduces NOx (though I don't think at all times, hence the NOx sensor before the SCR). The non-DEF LNT method (on my 2009 Cummins Bluetec) uses an absorption method (Lean NOx Trap). When that "trap" has absorbed all the NOx it can.. the Regen for the LNT (different from DPF regen) burns off the NOx using fuel in the exhaust stream. Since SCR uses no fuel for regen of the SCR, and uses small amounts of DEF.. the SCR technology has won the competition since it yields better MPG, and with less engine oil fuel dilution problems associated with post injection for the Regen events, no no diesels use the LNT emissions system.
> 
> https://www.dieselforum.org/about-clean-diesel/what-is-scr
> 
> Also, the 2012 Jetta I had was LNT emissions.. and the "cheat" was a big contributor to the better MPG than it would otherwise not get with the proper LNT regens taking place.


So if I’m understanding this correctly, the SCR ‘cleaning’ process uses DEF and the DPF Regen uses diesel fuel. Both processes occur independently of each other.

Correct??

This is my 3rd diesel but never had all this emissions stuff to deal with. 

The 09 TDI required no DEF and the 06 Cummins 5.9 (2nd owner) was modified before I bought it so it never had any emissions stuff on it, no Cat, just a Magnaflow muffler and 4” exhaust (no emissions testing in my part of the state).

Never had a CEL in either vehicle with over 400,000 miles combined.


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## MRO1791 (Sep 2, 2016)

Rivergoer said:


> So if I’m understanding this correctly, the SCR ‘cleaning’ process uses DEF and the DPF Regen uses diesel fuel. Both processes occur independently of each other.
> 
> Correct??
> 
> ...


Your 09 Jetta had the LNT system.. that was an NOx Absorber, and it would absorb NOx (until tested!, it was not doing many regens, due to the cheat) then it would regenerate using fuel in the exhaust stream to react with the NOx to produce N2 and water... making the NOx "trap" ready for more action.

The SCR is totally different.. it is a catalyst bed, where the DEF can react with NOx in the exhaust stream. It never absorbs NOx, so it is never needing a "clean". The reason why the EPA mandates the warnings and reduced power if the DEF runs out, is because without the DEF, there is no absorption of the NOx, and hence no controls of NOx emissions, or very little, the EGR is another way to limit NOx production in the combustion chamber, and the new Diesels are running lower compression ratios which also helps limit NOx in the combustion process. EGR has been very problematic in other ways, and they are looking to not use EGR in the future, but I thing SCR will be around for the long haul. 

Your 06 Cummins would not have been made with any of this stuff, the requirements came in force in 07.5, and the first trucks had many, many issues. 

The DPF Regen uses fuel primarily to attain the very high temperatures needed to complete the burn on the accumulated soot, the fuel use in that case is to get the temperatures up to burn the soot.. where with the LNT trap temperature was only part of the action, the other was the need for the un-burned hydrocarbons to react with the absorber to chemically combine to produce N2, CO2, and water.. and with that clear out the accumulated NOx in the trap. 

The LNT on my Cummins ('09) requires more than 30 minutes to complete a regen, on the Gen 1 Cruze its at most 20 minutes, and that difference is largely due to not having the LNT, the SCR is much better technology, but more complex, more expensive, and hence the VW cheat which literally saved $330 per car.. had they done SCR back in 2009, and not cheated they would have been much better off.. but they also saved $600 per car to use a very crappy HPFP that had epic failures... so I'm glad I got rid of that car fast once the data started adding up.


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## 91794 (Mar 25, 2015)

An actual DEF gauge would be best, always displayed, just like fuel level. That would be a cool software change for the dashboard and would help to minimize refilling both diesel and DEF for 3000 mile drives during record setting subzero conditions with occasional blizzards.

Is DEF level available via OBD port? Hmm....... 


Sent from my iPad using Tapatalk


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## obermd (Mar 3, 2012)

eli said:


> An actual DEF gauge would be best, always displayed, just like fuel level. That would be a cool software change for the dashboard and would help to minimize refilling both diesel and DEF for 3000 mile drives during record setting subzero conditions with occasional blizzards.
> 
> Is DEF level available via OBD port? Hmm.......
> 
> ...


Now this is a good idea. Even if it's like the OLM where you have to select it this would be a useful feature for diesel owners.


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## boraz (Aug 29, 2013)

eli said:


> An actual DEF gauge would be best, always displayed, just like fuel level. That would be a cool software change for the dashboard and would help to minimize refilling both diesel and DEF for 3000 mile drives during record setting subzero conditions with occasional blizzards.
> 
> Is DEF level available via OBD port? Hmm.......
> 
> ...


how would a def gauge minimize diesel filling?


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## boraz (Aug 29, 2013)

Rivergoer said:


> So if I’m understanding this correctly, the SCR ‘cleaning’ process uses DEF and the DPF Regen uses diesel fuel. Both processes occur independently of each other.
> 
> Correct??


yes


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## Duramax_7 (Nov 26, 2015)

Taxman said:


> JohnARM said:
> 
> 
> > The DEF tank does not need to be filled as often a the fuel tank. It is not like fuel will go 700 miles but DEF only 300. The opposite is the case.
> ...


There is a 1000 mile warning but it’s easy to miss because the message appears once and then it’s gone.


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## Taxman (Aug 10, 2017)

Duramax_7 said:


> There is a 1000 mile warning but it’s easy to miss because the message appears once and then it’s gone.


You don't have to manually dismiss it with the OK button like you do with 'service airbags' or 'tire pressure low'?


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## obermd (Mar 3, 2012)

boraz said:


> how would a def gauge minimize diesel filling?


It won't, but like a gas gauge when it starts to get below your comfort level you can decide when to refill the DEF. I'd rather refill fluids on my own schedule than have the car force me to do it when it's inconvenient.


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## Tomko (Jun 1, 2013)

obermd said:


> It won't, but like a gas gauge when it starts to get below your comfort level you can decide when to refill the DEF. I'd rather refill fluids on my own schedule than have the car force me to do it when it's inconvenient.


My suspicion is that GM has given consideration to offering a real-time running percentage of the DEF tank - but ruled it out. 

Two reasons that I can think of:

1) DEF goes bad with time and temperature. If someone was regularly topping off their DEF at 75% - or even 50% - the risk of the entire tank of DEF spoiling is increased exponentially from our current _Level OK_ until it starts offering a percentage ~35%. 

2) DEF feeezes. Frozen DEF may result in falsely low percentage readings in the tank. Therefore a frozen DEF reading of 50% may be equivalent of an unfrozen reading of 75%. Again causing problems by stimulating an unnecessary topping off of the DEF tank.


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## obermd (Mar 3, 2012)

Tomko said:


> My suspicion is that GM has given consideration to offering a real-time running percentage of the DEF tank - but ruled it out.
> 
> Two reasons that I can think of:
> 
> ...


The Volt has the same issue with item 1 - GM solved it by tracking the average age of the gas in the tank and when it hits a year old the car will burn the gas until it either runs out of gas or you put in at least two gallons of gas to "freshen" the gas. This is why many Volt drivers don't keep more than a third of a tank of gas in the car. There's no reason the DEF age couldn't be tracked as well.

Item 2 is a different issue, but as long as the reading is low the car will still not run out of DEF before the gauge says it will. Now if you got erroneous higher readings this would be a problem.


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## boraz (Aug 29, 2013)

obermd said:


> It won't, but like a gas gauge when it starts to get below your comfort level you can decide when to refill the DEF. I'd rather refill fluids on my own schedule than have the car force me to do it when it's inconvenient.


gen1 car the def tank lasts the oil change interval...like still 30% left in the tank....no reason to be uncomfortable

gen2 car tank is smaller, but its still not a daily or weekly concern

neither car stops you from adding def at any point you can add daily if you want, no harm.


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## boraz (Aug 29, 2013)

Tomko said:


> My suspicion is that GM has given consideration to offering a real-time running percentage of the DEF tank - but ruled it out.
> 
> Two reasons that I can think of:
> 
> ...


bad def isnt a thing.

its company policy to fill the def in our trucks daily

we carry jerry cans of def for when fuelling in the bush (no def available) that def could be in that jerry can for months

ive still yet to see a truck or meet a mechanic that has worked on a truck that has been down due to bad def.


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## MRO1791 (Sep 2, 2016)

boraz said:


> bad def isnt a thing.
> 
> its company policy to fill the def in our trucks daily
> 
> ...


As cold as it is in Canada might be why. DEF does have a shelf life, but when cold, or frozen it can last indefinitely, at high temperature it does break down, perhaps Canada doesn't have high temperature long enough for it to ever become a problem.. but a low miles Florida car could be a totally different thing altogether.

https://www.google.com/url?sa=t&sou...UDKkQFggwMAM&usg=AOvVaw2colFaMdas_6wZwiX2-1Wl


Sent from my Moto G (4) using Tapatalk


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## boraz (Aug 29, 2013)

MRO1791 said:


> at high temperature it does break down


ive still yet to seen proof of this or heard of it.

youd need 100f for 6mos 24hrs a day for it to degrade

the vehicle would simply dose more def to get the job done.


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## MRO1791 (Sep 2, 2016)

boraz said:


> ive still yet to seen proof of this or heard of it.
> 
> youd need 100f for 6mos 24hrs a day for it to degrade
> 
> the vehicle would simply dose more def to get the job done.


There have been issues..http://www.thedieselstop.com/forums/showthread.php?t=299707

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## 91794 (Mar 25, 2015)

Ancient Proverb adapted for your diesel cruze:

Before leaving on a mission of vengeance in your Gen 2 Cruze Diesel, dig two graves, and top off the DEF .


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## boraz (Aug 29, 2013)

MRO1791 said:


> There have been issues..Bad DEF fluid? - Diesel Forum - TheDieselStop.com
> 
> Sent from my Moto G (4) using Tapatalk


nowhere in the thread you posted does it show bad def was a thing.

if the post scr sensor gets a reading it doesnt like, CEL goes on and the culprit is claimed to be bad def.

but the car cannot test for def quality, just whether or not the end result is proper.

every single time the cause is not bad def, its bad sensor or something else, but not the def itself.

again, no car knows whether the def is good or not, just that the nox is too high, so OMG THE DEF MUST BE BAD....but it never is.

ask diesel mechanics how they test for def....they dont...there are refractors and testers to test def quality that shops and mechanics can buy...but they dont, they use a clear water bottle...pour some def in it, shake it up....yep, it looks like def.

test done.

because its never bad def.


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## MRO1791 (Sep 2, 2016)

boraz said:


> because its never bad def.


Just because you haven't seen it, nor does it seem to be a frequent occurrence, that does not mean "its never bad". That is objectively false. If you say it is unlikely, and you have never seen it, or that is seems it has never been proven in your experience.. that is OK, but you are incorrect and just factually WRONG to say it is "never" bad. It does degrade over time, and it degrades based upon storage temperature and exposure to light.. so some DEF sitting on a shelf in a warm, bright place for a couple of years, then put in a car, is quite likely to be be an issue.. Certainly it would be ill-advised to tell someone to not worry about old DEF that was kept in a warm bright place. That is the point. You tell people here is is "never" bad and you are leading some to eventually find out the hard way that it can be, in perhaps rare, even unlikely circumstances.. but it's just not true to say "never". Words matter. 

https://www.cumminsfiltration.com/sites/default/files/MB10033.pdf

From this document, and it can be found in many other places: 

Q. What is the shelf life of DEF?
A. The shelf life of DEF is a function of ambient storage temperature. DEF will degrade over timedepending on temperature and exposure to sun light. Expectations for shelf life as defined by ISO Spec22241-3 are the minimum expectations for shelf life when stored at constant temperatures. If storedbetween 10 and 90 deg F, shelf life will easily be one year. If the maximum temperature does not exceedapproximately 75 deg F for an extended period of time, the shelf life will be two years.

Q. What impact will exposure to high temperatures for an extended periodof time have on DEF?
A. While DEF exposure to constant, high storage temperature may have some impact on shelf life, thisshould not concern operators. Extensive testing in very hot climates has been conducted confirming thatDEF stored at a constant temperature of 95 deg F had a shelf life of over 6 months.

Q. What happens if a non-DEF substance is accidentally entered into theDEF tank?
A. The SCR system will recognize solutions other than DEF, and the DEF indicator light will appearnotifying the driver. Depending on the level of contamination in the tank, the vehicle may requireservicing.


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## boraz (Aug 29, 2013)

MRO1791 said:


> Just because you haven't seen it, nor does it seem to be a frequent occurrence, that does not mean "its never bad". That is objectively false. If you say it is unlikely, and you have never seen it, or that is seems it has never been proven in your experience.. that is OK, but you are incorrect and just factually WRONG to say it is "never" bad. It does degrade over time, and it degrades based upon storage temperature and exposure to light.. so some DEF sitting on a shelf in a warm, bright place for a couple of years, then put in a car, is quite likely to be be an issue.. Certainly it would be ill-advised to tell someone to not worry about old DEF that was kept in a warm bright place. That is the point. You tell people here is is "never" bad and you are leading some to eventually find out the hard way that it can be, in perhaps rare, even unlikely circumstances.. but it's just not true to say "never". Words matter.
> 
> https://www.cumminsfiltration.com/sites/default/files/MB10033.pdf
> 
> ...


and we're back at square one


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## 91794 (Mar 25, 2015)

^^^^^^^ DEF Comedy Jam ^^^^^^^


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## DslGate (Jun 29, 2016)

boraz said:


> gen1 car the def tank lasts the oil change interval...like still 30% left in the tank....no reason to be uncomfortable
> 
> gen2 car tank is smaller, but its still not a daily or weekly concern
> 
> neither car stops you from adding def at any point you can add daily if you want, no harm.


I've been going >5000 miles to a DEF tank refill, so I am curious ax to how the OP could be using so much DEF? one round trip to FL, approx 3000 miles total did not require a DEF top off, but when I did, it only took about 2 gallons, not even the whole 2.5 of Ad Blue I had.


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## DslGate (Jun 29, 2016)

eli said:


> Ancient Proverb adapted for your diesel cruze:
> 
> Before leaving on a mission of vengeance in your Gen 2 Cruze Diesel, dig two graves, and top off the DEF .


That was DEFinitely funny, but you need to DEFine mission of vengeance and not DEFer to just topping it off.


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## MRO1791 (Sep 2, 2016)

DslGate said:


> I've been going >5000 miles to a DEF tank refill, so I am curious ax to how the OP could be using so much DEF? one round trip to FL, approx 3000 miles total did not require a DEF top off, but when I did, it only took about 2 gallons, not even the whole 2.5 of Ad Blue I had.


I also use very little DEF..but the general rule is 2-3% of fuel use, and a big variance for driving patterns. I think it uses more DEF on coasting and idle than highway under load also. Conditions where there is excess oxygen in Combustion, thus light throttle.. ironically that would imply better MPG, but it also implies speeding up and slowing down.. hence more likely city where the overall MPG is less. Many factors affect DEF usage.

Sent from my Moto G (4) using Tapatalk


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## MP81 (Jul 20, 2015)

You're going to use more DEF anywhere NOx emissions are higher - which are tied to combustion chamber temps. Since diesel runs at such a high compression ratio, NOx emissions are quite high - hence using the DEF to reduce them down. 

With a diesel, you'll probably see peak chamber temps just off idle. So driving more city would theoretically use it quicker.


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## snowwy66 (Nov 5, 2017)

If you guys were smart. You'd be hitting the truck stops for def. They have them at the pumps. Which means a nozzle instead of a jug. AND, it's 50% cheaper at least. 

You don't see or hear of semi's buying the expensive box crap and trying to fill their 20 gallon tanks. That would cost twice as much and take 10 time longer to fill. 

 

And that BAD DEF light. Is the same thing as the check engine light. Doesn't mean the def is bad. It means there's a trouble code. 

I could see def going bad though. Specially in hotter climates. As the liquid content would evaporate and you're left with residue. For as many miles as you all get on 1 tank. I don't see any reason to actually be storing a box of the stuff though. Just fill the darn thing up every other fuel fillup.


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## MRO1791 (Sep 2, 2016)

snowwy66 said:


> If you guys were smart. You'd be hitting the truck stops for def. They have them at the pumps. Which means a nozzle instead of a jug. AND, it's 50% cheaper at least.
> 
> You don't see or hear of semi's buying the expensive box crap and trying to fill their 20 gallon tanks. That would cost twice as much and take 10 time longer to fill.
> 
> ...


The Cruze DEF tank is only about 4 gallons (slightly less Gen 2, slightly more Gen 1), and in most cases it will get about 5000 miles, or even much more on that small tank.. so it's not that often that it needs a fill, and even then not very much. Walmart sells a 2.5 Gal jug for about $8.. that's pretty cheap, and for many much easier to find a Walmart than a truckstop, depending on where you live of course. I only ever add a 2.5 Gal jug when it starts counting down, as it's not empty and will then take that much, but not much more. It's not worth the hassle to top it off and spill it all over the place.


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## snowwy66 (Nov 5, 2017)

MRO1791 said:


> The Cruze DEF tank is only about 4 gallons (slightly less Gen 2, slightly more Gen 1), and in most cases it will get about 5000 miles, or even much more on that small tank.. so it's not that often that it needs a fill, and even then not very much. Walmart sells a 2.5 Gal jug for about $8.. that's pretty cheap, and for many much easier to find a Walmart than a truckstop, depending on where you live of course. I only ever add a 2.5 Gal jug when it starts counting down, as it's not empty and will then take that much, but not much more. It's not worth the hassle to top it off and spill it all over the place.


The nozzles work just like gas nozzles. But i hear ya on the box.


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## johnmo (Mar 2, 2017)

I fill at a truck stop that's along my commute if I go the alternate route that's a little longer. Either way, I have to go to a retail location to obtain DEF.

I have to go inside and pay in advance for DEF at the truck islands. No swipey-swipe at the pump. Either way I have to go into a retail location and pay in advance for DEF.

I've never seen DEF as cheap per gallon in a box as I've seen at the pumps. We'll call that one a wash.

When I fill at the pumps:
-the tank gets filled to capacity, so I get maximum time and range between fills and I have to do it less often
-I don't have to lug gallons of DEF to my car
-I don't have to store any leftover DEF --or any DEF at all -- at my house
-It's easier to fill with a nozzle from a pump with an automatic cutoff than it is to lift up and hold gallons of DEF while the box drains

Advantage: truck stop pumps. If they're available anywhere near you, try them. You'll like them.

One tip about the truck stops: hit them after work rather than before. Truck islands are really busy in the morning because the drivers are topping up and starting their day. I don't think I've ever had to wait for an open pump, but I think I did have a truck waiting on me to finish once in the morning. I try to get in and get out quick because I know they're on the clock.


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## BlueTopaz (Aug 25, 2012)

Luckly there is a diesel station close to me that has DEF at the pump. Super easy to fill and no mess, not to mention it is less expensive than the bottle stuff.


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## mkohan (Dec 19, 2015)

I find Saturdays a good day to fill the DEF tank at the truck stop.


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