Diesel Exhaust Fluid

[Wandering Sagebrush]

I was recently on Steens Mt. and had a diesel exhaust fluid system failure warning on my 2014 6.7L Ford. It said I would be limited to 50 MPH in 50 miles. So after 50 miles of nagging warnings, I assume it did limit my speed, but I wasn’t in a place to try to go faster. At about 52 miles, I pulled over to speak with Mother Nature, truck idling. When I got back in the truck, the fault cleared, no limitation on speed.

Yesterday, I took the truck in for routine service, and had them check for fault codes. No codes present. They asked what DEF I used (Peak Blue DEF), and told me that 60+ percent of issues they saw were diesels that used Peak. There are a number of factors that could be involved, ranging from sales percentage, to storage and shelf life issues. All that said, I’m going to switch to MotorCraft from the dealer, as it is roughly the same price as Peak, or if in bulk, less expensive. Just drive by and top off the DEF tank.

Apparently, the DEF failure Issue isn’t just a Ford issue. A friend with a 2016 Dodge has had similar experiences. I suspect GM is affected, too.

Has anyone on WTW experienced DEF problems with their diesels?

 

[lmwilco1]

No issues on my 2013 F350, I go to the Loves truck stop and buy it from the pump where the truckers fill up. I bought a pump nozzle magnet because it was always a pain getting one from them.

 

[Outnabout]

No issues on my 2013 F350, I go to the Loves truck stop and buy it from the pump where the truckers fill up. I bought a pump nozzle magnet because it was always a pain getting one from them.

What is a pump nozzle magnet?

 

[lmwilco1]

The big rigs have a magnet in the filler neck that opens a valve on the def pump to prevent them from pumping DEF into the fuel tank. If you don't have the magnet the def barely dribbles out and you won't be able to fill your tank. Try searching for:

Five Star DEF DEF Magnevator

 

[Zoomad]

After speaking to GM technical assistance at length about DEF fluid I have a few takeaways. GM obviously recommends to only use AC Delco brand DEF fluid. But the rep I was talking with did go into a little more detail on DEF fluid in general. Def fluid has a shelf life. That shelf life can be reduced by exposure to UV light and high temps. It's why the bottles are shipped and stored in cardboard boxes.

There should be a production date on the package to know just how old the DEF fluid is. You want the freshest stuff you can get. If a part store or gas station has a big display up front by the windows you probably don't want to pick them up. It also means you don't want to stock up on it and store it in your truck where it could be exposed to more heat or possible UV rays.

The older DEF is and the more it is exposed to UV or heat the less effective it is. The less effective the DEF fluid is, as it's injected into the exhaust there is less of a change to the exhaust and the higher potential for it to set codes for poor DEF fluid quality.

Buy when you need it and get the freshest you can get. Don't buy more than you need and store it outside of the cardboard box or in a spot where it can get exposed to high temps.

 

[Andy Douglass]

I only get Peak because it is pretty much the only brand I see, have not had a problem (Ram). I would never buy a dusty or otherwise aged looking box, but I have not bothered to learn the date code system so I never check the date. I have heard the bad DEF thing a lot, but I don't know that I believe it. I will have the same DEF sitting in my tank for 6 months or more, and that has to be pretty common with the quantity of diesels that get sold now. Does a cardboard box pass significantly more UV than the DEF tank on my truck? I don't know but it's plausible. Does UV actually degrade DEF? I don't know. I would think evaporation would be the biggest factor as that could trigger urea crystallization which might significantly change the concentration in the DEF. But that is just a guess.

The fact that your fault code cleared without any change to the DEF in your tank would argue against it being bad DEF. Why would the DEF suddenly improve quality just sitting there? I think the most likely cause for DEF fault limp mode activations is probably just the complexity of the system. Who knows what might go wrong with all that witchcraft going on in there? Condensation on a DEF sensor? That might tell the system that you are an eco-criminal who tried to destroy the environment by putting plain water in your tank.

 

[kmcintyre]

Interesting. We were out at the Steens just before you but to your question. I've not had any issues using Peak. Now one option that I don't do and you may not be an option for people. If you have a tune, many times they do something where you can use distilled water rather than DEF. I have no idea what they do (turn it off) and not sure I'd risk it but it might be an option in an emergency. I would google it and decide if that's an option for your vehicle. Also, DEF isn't really that magical fluid so I could see where the water solution might work on a tuned engine.