DEF tank refilling

[mdirads]

How low should we let the DEF tank go before refilling?

 

[n8zcc]

On both of mine, I let the needle fall into the red zone then add a 2.5-gallon jug. That raises the needle up to just under the 3/4 mark.

 

[Rebelguy2020]

I also add a 2.5 gallon jug when the truck says “Add DEF or vehicle will not start after 500 miles”. It gives you a long warning.

I kept four empty 2.5 gallon jugs and fill them at trucker’s pump station, it is 1/4 to 1/3 the price. I always rinse the jugs and spout after emptying and then let it dry before placing the cap on the jug, if you don’t rinse it it will get crusty flakes everywhere.

I store the empty and full containers in my garage, out of the direct weather.

 

[mdirads]

This is my first diesel, and I bought it in September 2022. I have approx 4300 miles, and still on the original DEF tank from the dealer. I'm about 1/3 into the red zone on the gauge. Good to know about the warning. Thanks

 

[jent]

I let it go till the warning starts. In part because I want to get the old def out of the tank rather than just dilute it with fresh def.

If I have a road trip I always bring an extra box with (there are times in extreme wind I have burn through def as fast as I was burning through diesel it seemed).

 

[dmitriy]

FYI if you tow the DEF tank will suck down quick. (seemed like 1k miles to 2.5gal if I remember correctly)

 

[mdirads]

I let it go till the warning starts. In part because I want to get the old def out of the tank rather than just dilute it with fresh def.

If I have a road trip I always bring an extra box with (there are times in extreme wind I have burn through def as fast as I was burning through diesel it seemed).

that was my thought process. appreciate the reply

 

[drydocked]

The DEF used is a percentage of the fuel burned, I forget now if it's supposed to be 2% or 2.5% DEF to diesel. Use more fuel towing and you'll use more DEF.
I always wait until the low DEF light comes on, then add a 2.5 gallon box like the others above.
The first winter I had the truck it sat for 3 months not long after I had filled the DEF to the top at a truck stop, and I had a check engine light related to the DEF when I started driving it again. The dealer fix was flushing the tank and sensors and said that RAM is recommending not filling the tanks to the top and always using fresh DEF to avoid sensor problems, so that's when I started adding only 2.5 gallons at a time. It sat again this winter from Dec to early March and no problems this year with the sensors.

 

[Sascwatch]

Could be a coincidence, but the first time I ever let my 2020 run until the def warning came on the def level sensor stopped working and even after refilling the def the fluid level was never recognized. The entire def tank had to be replaced as the sensor is not available on its own.

Ever since I had that issue I fill up the def around 1/4 tank, well before the countdown begins. I do enough towing that I never worry about the def going bad, fill the tank 4-5 times per year.

One thing I found odd was that on a recent trip through northern Ontario while towing is that once the temperature warmed up above -10C I could actually watch the gauge go down as I drove, it’s as if the tank was frozen and once it thawed the level sensor caught up to itself.

Also save your def jugs and refill them at a truck stop if you are going on a long trip while towing, the bulk def is less than half the cost of a jug in my area. Price gouging is crazy when buying it by the jug at gas stations along the highway.

 

[Malodave]

I have had it down to 40 Miles left before. It just hit 230 miles the last time before I refilled it with two jugs.

Malodave

 

[TSL]

Recently filled mine to the top. Took 2 jugs less 8 oz from the second ( I measured the left over ). Was down to "300 miles to truck not starting" when I refilled. By my calculation I got 4400 miles on the previous tank. No towing though.