What DEF Fluid?

[DaveL]

There's a lot of things I like about it - in no particular order:

1) It shows me when I'm in a regen cycle. I never want to stop it in the middle of a regen - if I can avoid it. I know it's designed to handle it, but if I can take the long way home and let it finish its regen cycle, plus let the exhaust system cool down a bit, that will help extend the life of everything. It can't be good for the system to shut down at 1100F+ inside the DPF...

2) I like to see engine oil temp. This engine runs hot - the coolant is often in the 210F range and it's used to cool the engine oil in a stacked plate cooler mounted to the side of the engine. Hot coolant means there's less delta T between the two fluids so therefore engine oil stays hot. I see oil temps at ~220F unloaded and above 250F most of the time when I'm towing. I saw 260F once, but then promptly saw the coolant plummet to 185F so that must be a threshold programmed into the ECM.

3) I get to see what gear I'm in. It's amazing how little this engine needs to downshift to go up inclines. A testament to how well things engine produces bottom end torque.

4) DEF level is a percentage and not a little chiclet on the dash info screen. As previously mentioned, once it's at 50% I dump in another jug.

5) Multiple pages for different configurations. I have one page setup for everyday driving - the other page setup for towing. You can have up to 5 pages configured.

6) Last but not least - I like its profile/size. I don't want a mini-tablet on my a-pillar. The IDash has a clean look, easy to read and is a subtle addition to my dash layout. My wife does not like clutter and this doesn't bother her in the least bit.

Thanks for all in the info!

 

[JayceeP]

Also don't buy DEF from a store that stores the stuff in windows (usually auto parts stores). Two things that will degrade DEF are heat and sunlight. If you store jugs at home keep in a cool place away from sunlight (like a basement).

How do summer temps impact DEF when it’s in the def tank of the vehicle?

 

[Jay P Wy]

How do summer temps impact DEF when it’s in the def tank of the vehicle?

So far no issues with the Tahoe but the 21 Ram/Cummins I had did have issues with DEF going bad in the summer. I usually only keep the DEF tank half full unless taking a long trip. If you have a Banks iDash or Edge CTS you can monitor DEF percentage (should be around 32%) and see if it's a problem. Sloshing around in the tank as you drive may also help.

 

[StephenPT]

So far no issues with the Tahoe but the 21 Ram/Cummins I had did have issues with DEF going bad in the summer. I usually only keep the DEF tank half full unless taking a long trip. If you have a Banks iDash or Edge CTS you can monitor DEF percentage (should be around 32%) and see if it's a problem. Sloshing around in the tank as you drive may also help.

Thanks for the heads up on the DEF concentration PID. I glossed over that one when setting up the pages on my IDash. I put it on my diagnostics page and I'll check it after putting in jug of DEF next time - my Yukon hasn't moved for a couple of days and currently it's at 33%.

 

[skydiver]

There's a lot of things I like about it - in no particular order:

1) It shows me when I'm in a regen cycle. I never want to stop it in the middle of a regen - if I can avoid it. I know it's designed to handle it, but if I can take the long way home and let it finish its regen cycle, plus let the exhaust system cool down a bit, that will help extend the life of everything. It can't be good for the system to shut down at 1100F+ inside the DPF...

2) I like to see engine oil temp. This engine runs hot - the coolant is often in the 210F range and it's used to cool the engine oil in a stacked plate cooler mounted to the side of the engine. Hot coolant means there's less delta T between the two fluids so therefore engine oil stays hot. I see oil temps at ~220F unloaded and above 250F most of the time when I'm towing. I saw 260F once, but then promptly saw the coolant plummet to 185F so that must be a threshold programmed into the ECM.

3) I get to see what gear I'm in. It's amazing how little this engine needs to downshift to go up inclines. A testament to how well this engine produces bottom end torque.

4) DEF level is a percentage and not a little chiclet on the dash info screen. As previously mentioned, once it's at 50% I dump in another jug.

5) Multiple pages for different configurations. I have one page setup for everyday driving - the other page setup for towing. You can have up to 5 pages configured.

6) Last but not least - I like its profile/size. I don't want a mini-tablet on my a-pillar. The IDash has a clean look, easy to read and is a subtle addition to my dash layout. My wife does not like clutter and this doesn't bother her in the least bit.

Don’t want to sidetrack the thread…
I have a 2022 suburban with the 3.0. I towed a 4500 pound trailer from Austin to Enid and back for our dogs first pheasant hunt. The truck performed beautifully (way better than my previous 2019 Expedition with eco- boost v6)
I got this with 33k in December. I had about 90% DEF tank when I left Texas. I had to refill def just north of the Texas border (50 miles till limp mode).
This seemed like a lot for only about 650 towing. I was driving faster than I used to drive the Expy (avg75mph) and still got 12mpg (compared to 7.5 mpg on the expy)
I definitely have picked up a lot here about def.
I just installed my dash this past weekend. I would love to know what sensors you have on your daily driving page as well as your towing page.