[boraz]

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

 

[boraz]

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.......


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how would a def gauge minimize diesel filling?

 

[boraz]

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

 

[boraz]

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.

 

[boraz]

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.

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.

 

[boraz]

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.

 

[boraz]

There have been issues..Bad DEF fluid? - Diesel Forum - TheDieselStop.com

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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.

 

[boraz]

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.

and we're back at square one