Tip Buying DEF from pump

[Neal]

You're probably tired of hearing me say it but I never use pump DEF in my coach. To many reasons not to and its of no benefit to me to fill at a truck stop - it takes longer, I’d have to move the coach since the DEF fill spout is 30’ from the fuel fill, and with jugs I can fill at my leisure when stopped anyway. And since I get around 300mpg on DEF its pretty easy to plan ahead, buy enough fresh DEF for a trip and not over buy.

Yes, you have to pull forward which is not a big deal to me. Pump diesel, which I leave the engine running, pull forward, pump DEF. It's all a matter of personal pref but if you don't trust pump DEF do you trust pump Diesel? Why any difference? Just like any fuel or DEF for that matter, I'm sure it has regulations that govern the filtering, storage, etc. If they offered box Diesel would you use that instead?

I personally think the box vs pump is overblown but it doesn't matter. Everyone does what they want to do. We can all nay say either way. We just hope whatever we are getting from whatever source is quality and not going to cause us any problems. My guess and only a guess is a lot more consumers are using pump DEF (i.e. truckers) than boxed products so if there is going to be a problem it's going to affect a lot more. It sucks either way. These RV myths are always interesting to read, just like the always keep DEF full (which I also don't do, what's the net age of your DEF after 5 years?) vs. cycle it at 1/4 to 1/2 DEF levels as I do. Again, do what you want in the end.

In @lostinfla's case, it sucks, whatever happened or if the DEF was contaminated. Bad deal!

Moral is: I have to trust the fuel coming out of the pump for my car. I have to trust the fuel coming out of the pump for my plane. Why does this change for RV with diesel or DEF?

 

[Rich W.]

Just a couple comments on that: Diesel is a lot more stable and diesel engines have very good on-board filtration compared to DEF, but you still have to be careful and I wont fill up if a fuel truck is dumping a load at the time. Bad fuel can still leave you stranded but its much less common and I carry spare filters just in case. I also carry a spare DEF filter. But the main thing about box DEF is its more controllable and verifiable than pump DEF which is important (to me) since these emissions systems have proven to be so fragile. All it took was a couple ruined trips for me. It may or may not make a difference for the most part, but it is something I can do to have a little more control over the situation, and I also prefer dumping a jug in every few days at my leisure - that part is just preference.

I don't know what the primary rationale is for keeping the DEF tank full or if its even a prevailing concern. For pre 2016 systems it makes sense to keep the mechanical float in the tank from gumming up. For 2016 and later systems, I can’t see how it would matter. But if I rotate 7 - 10 gallons of DEF through my tank on a given trip, the DEF is staying fresh enough given a shelf life of up to a year in 70° - 80° temps. If the tank sat full over a summer at 100° temps, I’d dump it and put in fresh, but keeping it full would still protect the float, and false “low DEF” signals have been responsible for many if not most of the pre-2016 system DEF header failures (hence the TSB I often post).

I don’t operate on trust or myths - I verify as much as possible and take control of whatever I can. I started this DP journey knowing basically nothing about the emissions system and it left me stranded twice on important trips, had me scratching my head quite a few times before I figured it out. I was a trial and error experience with shops trying to charge me for parts and service I didn’t need and repairs that we covered by the emissions warranty.

As I progressed through this learning experience I often read accounts of people spending thousands of dollars to either correct avoidable problems, for repairs that were actually covered under the emissions warranty, or for completely unnecessary work. Its happening as we speak and I have decided to do everything I can to prevent it from happening to me so I can enjoy my coach and make my own decisions on where I spend my money. Ruined trips and inflated and unnecessary repair bills are not good for my vacation and leisure effort. I also study problems that others have had to prevent experiencing them myself, and I try to share what I’ve learned in hopes it helps some folks. Sometimes it does, and sometimes it doesn’t.

Ok that was more than a couple….

 

[Rich W.]

Also for comparisons sake, diesel, gasoline, av-gas, jet fuel, etc have been around a long time and the systems that use them have been perfected over many years. Putting scrubbers in vehicles is a relatively new concept and it was mandated far before the systems were close to being ready, much less perfected, and with no regard for causing drivers to be stranded, wether in personal or commercial vehicles. In fact intentionally stranding the vehicle is one of the parameters built in to the systems, even in public transportation including school busses, and it wasn’t until 2013 that exemptions were developed for emergency vehicles and harvesting equipment. But obviously the systems were faulty and problematic since these exemptions were needed. Even now, 13 years later, the technology hasn’t been perfected but it is a lot better and for the most part, the problems are subsiding in newer vehicles. But you would never see this kind of reckless disregard for operability or safety in the aircraft industry where everything is fully tested before being implemented, and aided by redundant systems. Unfortunately that same level of regard or concern has been withheld from those of us who operate on the ground.

 

[lostinfla]

I should also say that in the 8 years or so of DP ownership after many gasoline powered rigs, I always bought DEF at the pump and never had an issue, but, once is enough for me. If I can take any steps to avoid problems while on the road, I'll not step, but run in that direction.

 

[Neal]

I should also say that in the 8 years or so of DP ownership after many gasoline powered rigs, I always bought DEF at the pump and never had an issue, but, once is enough for me. If I can take any steps to avoid problems while on the road, I'll not step, but run in that direction.

I just hope what you experienced is not a red herring and in fact was the DEF. But it could be a sign that something is wrong and keep close attention, have that DEF head simulator if you don't have one, etc.

 

[Joe doggs]

I just hope what you experienced is not a red herring and in fact was the DEF. But it could be a sign that something is wrong and keep close attention, have that DEF head simulator if you don't have one, etc.

Excellent advice Neal,the op mentioned the def smelled like an “overfilled cat litter box”….if any def has a strong ammonia smell…stop,do not use it…the def sensor simulator cut the whole def head problem down to little more than an inconvenience if a def head goes bad…..an additional measure of course is using the refractometer before dispensing any def…..I have felt for awhile that truck stop def is fresher than wal mart,or Napa,and likely an average cooler storage temp depending on location of course…..my x15 Cummins uses quite a bit of def under normal use(approximately 5%) so buying,rotating,storing jugs of def is inconvenient compared to truck stop def,and something that isn’t worth the hassle(or expense)to me…..and in my opinion unnecessary with a def head simulator and a refractometer to boot…..happy travels jb

 

[Rich W.]

I just hope what you experienced is not a red herring and in fact was the DEF. But it could be a sign that something is wrong and keep close attention, have that DEF head simulator if you don't have one, etc.

Lostinfla may or may not be aided by the DSS since it only works on 2016 and later emissions and 2016 coaches can have either depending on when the chassis was built. My 2016 is on a 2015 built chassis so it has pre-2016 emissions. It’s easy to check by looking at the connector on the DEF header. If it has this plug you have 2016 and later emissions:

If it has a flat plug the system is pre-2016 emissions and the DSS will not work. This the the header side of the pre-2016 plug:



I bought the parts to build a DSS when they were first developed only to find out it wasn’t compatible with my DEF header so I sold the stuff. But pre-2106 emission systems are also less vulnerable since they don’t have the “qual” sensor which was the cause for many DEF header failures. With pre-2016 emissions the main thing you can do is keep the DEF head wet with a nearly full tank and change the filter annually. Those two things along with fresh DEF will prevent most of the problems.

I recently found that the station I bought pump DEF from before my two DEF related problems stores their bulk DEF in an above ground tank. Its also a small, local, member only station, so very low volume sales compared to a busy truck stop. With a shelf life of two months above 100° and relatively low stock rotation, it seems likely that DEF stored this way in the summer could be bad. Below ground storage and high volume sales of a busy truck stop would seem to me to result in much more dependable DEF. And of course as I’ve said before it could all have been coincidence.

 

[Neal]

When I bought mine at Hoots he wanted us to bring a picture due to this. He saw my yellow connector and said I was good. 2017

 

[lostinfla]

I've got the older DEF head, thank goodness. If I had the newer unit, I probably would have been dead in the water.

 

[Joe doggs]

Might be best to use the refractometer every single time you add any def in that case,and/or if possible use high volume underground storage def…I’ve always noticed that loves,pilot,flying j are perhaps the highest volume stops…although def is the only thing I buy at the big truck stops…..