DEF warning

[larryq]

Got the dreaded 200 miles to speed limit of 5mph today.

had to drive for work 90 miles one way.

watched the fuel, but the def got used at an accelerated rate!
Thank God, it didn’t go off where I had to go!
2 horse town!!

anyway got a bottle and all is good.
My issue is with the safety of this.

if it had happens when I was on the road, that would have been 180 miles till back to civilization!!

Is there a way to re program the speed?
5mph is a little dangerous!!

 

[NIsaacs]

???

 

[AH64ID]

Got the dreaded 200 miles to speed limit of 5mph today.

had to drive for work 90 miles one way.

watched the fuel, but the def got used at an accelerated rate!
Thank God, it didn’t go off where I had to go!
2 horse town!!

anyway got a bottle and all is good.
My issue is with the safety of this.

if it had happens when I was on the road, that would have been 180 miles till back to civilization!!

Is there a way to re program the speed?
5mph is a little dangerous!!

We’re you running out? Or is something wrong?

It reads like you were just running low. If you run out of DEF at least you get 5mph, if you run out of diesel you get 0mph.

You should have gotten a DEF low at approx 500 miles remaining, so that should have been a clue to fill up.

IMO it’s only dreaded if it’s accompanied by a CEL or other warning message.

 

[Cummins12V98]

Case of not planning ahead.

 

[kthaxton]

No, you cannot reprogram the speed, but you can put more DEF in when it is low....just like fuel.

 

[larryq]

I keep the level low in the hot weather.
The unplanned 200 mile trip tripped me up.

 

[lpennock]

I keep the level low in the hot weather.
The unplanned 200 mile trip tripped me up.

During the summer you could just keep a spare box of def in the house for these kind of situations. I'll do that and put it in when I'm heading out for a long trip. Shelf life in the house is at least a couple years.

 

[AH64ID]

I keep the level low in the hot weather.
The unplanned 200 mile trip tripped me up.

Evaporation is also hard on DEF, I’m not sure I’d keep it that low, too easy for it to get out of tolerance.

 

[Silver Tex]

New to the DEF crowd. I won’t be driving my truck much, typically 300 mile cabin trip and 5th wheel pulls. Should DEF be left full, partial, other? In those times where it could sit for a month, I would get it out on the highway a couple of times a month just to keep it lubed and loose. Thoughts?
Thanks.

 

[lpennock]

Where do you live? In real hot climates like Phoenix I would keep minimum amount of DEF in the tank in the summer as the shelf life is only 4 months at 104 and 1 month at 122. In cooler climates you can leave full as shelf life at 95F is 10 months and at 86F is 23 months.

 

[Silver Tex]

Where do you live? In real hot climates like Phoenix I would keep minimum amount of DEF in the tank in the summer as the shelf life is only 4 months at 104 and 1 month at 122. In cooler climates you can leave full as shelf life at 95F is 10 months and at 86F is 23 months.

Front Range, Northern Colorado.

 

[lpennock]

Front Range, Northern Colorado.

You are probably ok for shelf life either way. I personally like to run it down to the point I get the countdown warning before I refill it. That way I have the least amount of DEF when I fill it so I get maximum amount of fresh. I only put about 7.5k/yr on my truck and have to deal with Phoenix summers.

Others like to keep it top offed so there is minimal evaporation that could increase the UREA concentration percentage.

 

[AH64ID]

We get temps above 100° a few days a year, but I’ve never managed my DEF based on shelf life. Drive it until the low light comes and and fill it full, unless I know I’ll need more for a road trip.

I do put about 15K/miles a year on the truck, which averages about 17 gallons of DEF a year. The bulk of my DEF use occurs when it’s hot and in the fall so that DEF doesn’t last long. I really don’t have a need to be concerned with shelf life.

 

[Wiredawg]

New to the DEF crowd. I won’t be driving my truck much, typically 300 mile cabin trip and 5th wheel pulls. Should DEF be left full, partial, other? In those times where it could sit for a month, I would get it out on the highway a couple of times a month just to keep it lubed and loose. Thoughts?
Thanks.

Like so many other topics, you will hear the full range of answers on DEF tank levels. I keep mine full, 9 gallons on a Cab and Chassis with no problems in SW TX heat. In 2019, I barely drove my 2017 Ram 5500 while recovering most of the year from a major surgery and no problems with DEF.

When I purchased the truck I asked my Ram service writer of 20 years what should I do WRT having a DEF truck and he advised keeping my DEF tank full. With 46K miles, mostly towing, no problems. I'm not scared of DEF, I fill with either truck stop bulk or fresh Wal-Mart jugs.

That's my method.

 

[bcbender]

I just filled mine a few weeks ago... I'll run it down to the light and fill again... Not driving as much this year due to fuel costs, but should use up the tank as Ron said without issues

 

[Silver Tex]

Thanks All!

 

[GBergen]

This article from RVTRAVEL tells about the EPA proposing a change to engine derate beginning 2027.
"Finally Possible DEF relief for Diesel trucks and RV's"
There is also a bit of information of what was requested by the EPA initially and what the engine manufacturers did in response.
It looks like it's up to the engine manufacturers to create a solution for the current population of trucks.

 

[Wiredawg]

Friends, for the first time owning my 5500, I've decided to call modify my fill plan. When I was pulling heavy trailers, I seemed to go thru DEF enough to avoid aging problems. No problems yet, but I decided to adjust my new full mark approximately 5 gallons. On my 9 gallon tank, 1/2 on the DEF gauge is approximately 6.5 gallons. ROM guess puts about 1/3 on the gauge where I want to be. Just thought I'd share as I've modified the use and duty cycle of my truck.

Glad this thread sparked my thinking on this.

Cheers, Ron

 

[Learjet]

Where do you live? In real hot climates like Phoenix I would keep minimum amount of DEF in the tank in the summer as the shelf life is only 4 months at 104 and 1 month at 122. In cooler climates you can leave full as shelf life at 95F is 10 months and at 86F is 23 months.

From a Ford doc:
"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."

 

[lpennock]

Fords example is good but is slightly flawed as it is based on long term averages. Phoenix summer average temperature has been steadily increasing and the number of 110+ days per year has also been increasing. So while 6 month based on the long term averages is correct, the average over the last 3-4 years would probably indicate a shorter time. For Phoenix I would still recommend keeping the minimum amount in the tank June-August then in September or October put good fresh DEF in that way you don't have to worry if shelf life is 3, 6 or 12 months.