Another DEF Question

[KHargarten]

I'm getting the dreaded 5mph warning. Pulled the injector, it's clear. Has anyone had DEF crystallize in the line? My truck can sit for a month between uses.

 

[bcbender]

How old is the DEF? My truck sits for extended periods also, but I try to run the DEF all the way out before putting more so that it never ages out.

 

[KHargarten]

How old is the DEF? My truck sits for extended periods also, but I try to run the DEF all the way out before putting more so that it never ages out.

It's about a year old.

 

[bcbender]

I was only asking as it has a finite shelf life, I live in NC so ambient temps are not an issue for me really, but folks living in the SW where it regularly gets above 90 could potentially run into issues of reduced potency. Not saying that's the issue or is an issue, but I know the trucks have a DEF quality sensor and I would assume if the DEF is not or no longer the correct ratio it would register the same as being low and begin a countdown to de-rate until the issue is resolved. Its also a reason I don't by from the local stores and only buy from high volume truck stops so I know its fresh and don't have to check date codes,.. I've seen some auto parts stores with DEF piled up in the window with the sun baking on it... not good for the shelf life.

 

[endoscott]

Pretty cheap tool for the kit. At least you could rule in or rule out the DEF concentration as the problem. Let us know how this turns out. We spend a lot of time in the desert heat and don't put a ton of miles on the truck except when we are on the road with it.

Amazon product ASIN B07DLDZBS8

 

[endoscott]

Whoops, the attachment didn't show up:

Amazon product ASIN B07DLDZBS8

 

[endoscott]

Not working, but type in "refractometer for DEF" on Amazon and several show up around $25

 

[Diesel85]

The newer trucks have an onboard DEF quality sensor and it is extremely accurate. In 3 months alone it can go from 32.5% on the nose, to 33% due to some of the water evaporating, thus concentrating it.

On my personal truck, I put in one container at a time, not fill the entire DEF tank with the freshest DEF. I also clean the filler area well with a reg before opening the cap.

You need to work these trucks and drive them almost every day.

 

[Grumpy8811]

I'm getting the dreaded 5mph warning. Pulled the injector, it's clear. Has anyone had DEF crystallize in the line? My truck can sit for a month between uses.

realistically you need to pull the codes and see what code they system is showing before proceeding down the diagnostic rabbit hole.

yeas, DEF has a shelf life but in general unless the truck is in Death Valley the stuff will last anywhere from a year in a hot climate to 3 or 4 years in a cold climate..
if you suspect its just piss poor DEF, siphon the stuff out of there and add some new DEF.

 

[KHargarten]

I'm concerned the injection line has solidified.

 

[Grumpy8811]

I'm concerned the injection line has solidified.

why is that?

 

[KHargarten]

why is that?

No buildup on the injector or the inlet.

 

[Grumpy8811]

No buildup on the injector or the inlet.

you know you need special diagnostic equipment to test this stuff.. and without knowing what exact code you have stored its a serious waste of time to guess as there are dozens of potential trouble codes associated with the DEF system.
.
I watched the tech at the dealer test mine of for flow, after the DEF pump failed, so he removed the hose and was able to run the DEF pump and test for flow
using his diagnostic computer. Without that type of equipment, this stuff is hard to diagnose.

I do think if you were able to remove the hose at the injector and at the pump end, you should be able to blow thru it with air pressure.

 

[Ozymandias]

Lines are purged back to the tank at every shutdown.
They are dry empty with the truck sitting.

 

[Signal73]

Lines are purged back to the tank at every shutdown.
They are dry empty with the truck sitting.

There is residual. I recently decommissioned my def and as part of the tank/injector/line cleanout process I blew out the line from the tank end to the injector end and there was definitely some left in it.
An interesting def shelf life from the big blue oval;

https://www.motorcraft.com/content/...st_Fluid/DEF Shelf Life and Fluid Quality.pdf

 

[Topzide]

Being put in limp mode, means that there is something more going on. What year truck, and how many miles? Could be the pump, SCR, Nox sensor(s). Without codes, throwing darts at the board! The line being plugged up, highly unlikely. If you had AlfaOBD, you could run pump to see injector work, and read codes. More info required before we can offer more help. Thanks.

 

[AH64ID]

If you think crystallization is a possible issue you can always dilute your DEF with distilled or deionized water. The truck wont care as long as you keep it above 22%. I found that down to 26% there was no increase in DEF usage rate.

 

[Diesel85]

If you think crystallization is a possible issue you can always dilute your DEF with distilled or deionized water. The truck wont care as long as you keep it above 22%. I found that down to 26% there was no increase in DEF usage rate.

You can also stretch your DEF usage that way too.

 

[AH64ID]

You can also stretch your DEF usage that way too.

I suppose, if you buy it in the carton. I prefer buying it at the pump so it doesn’t really stretch it.

 

[sag2]

You can also stretch your DEF usage that way too.

Not sure it actually stretches the use. If the injector is dosing at a specific rate and the NOx is not being completely converted, the system will increase the injection rate to get the NOx reduction in range.