I have 5,600 miles on my truck. I have yet to see a add DEF warning. Does the warning just flash on like the cleaning exhaust warning or does it stay on for a while? I don't watch the dash much.
Also, I am thinking of running Mobil 1, 10/30 oil. Isn't there a guart or two left in the engine after you drain the oil? Will the synthetic and Dino oil mix well enough to not do any harm. Since I am waiting until the truck tells me to change oil, which will probably up to seven thousand mile between changes, I want some good oil in there. I run Mobil 1 in all my motorcycles with good luck. I have never run synthetic in a four wheel vehicle. It's always been to expensive, but since I am waiting on the truck to tell me and it may get as much as eight thousand miles I think I can afford that. I was always a three thousand mile guy until now. I guess I'm getting old a lazy.
So what do ya think? Thanks guys

 

No you will see the def message.I cant remember exactly I think it comes on screen everytime you start truck and you have to aknowledge it to get it off screen and it will come back each and evry time you restart truck untill you add def....If I remember correctly...

I have a cts monitor now so I know where def level is at.I add def when Im at 50 percent.

 

You will get warnings at 800 k/m to empty.

Also in in the info screen you can check the def level, it will tell you if its ok or under 1/2 full, etc..

 

Newer trucks (mine is a 13) get the warning to add def @500 miles to empty.


@200 miles then everytime you start it up it will give you the count down.


I would not add till then.

 

Mine is also a '13. I get a "1/2 full" message and haven't let it get low enough for the next message. I find it will use about a gallon per 1000 miles. I'd suggest getting a jug of DEF and see how much you can add.
you will learn IF it's using any at all and if it's more than half full you haven't used enough to trigger the messages.
Have you seen the "Cleaning Exhaust" message?
I've read that driving style will affect DEF usage, low speed/stop and go using the most I think.

 

I would not add at all till you get the 200 miles till empty.


While you can add it anytime the system works best by running it down and then giving it a complete fill up.


Non towing will use less def. Truck will regen more.


Complete opposite with towing.

 

I haven't towed a great deal yet, no more than twelve thousand pounds and then only briefly. A few hundred miles at a time. I have a toy hauler that comes in at around seventeen thousand. I haven't had the luxury of pulling it yet. I live on the road and I am a full time RVer. Looks like I'll be here a few more years, jeez.
I have seen the "cleaning exhaust" a few times but I don't look for it. Just curious on how many miles ya get on a tank full of DEF.
I can't seem to find how much DEF is left on the message screen. I have seen it before, but I looked for it the other day and couldn't seem to find it. Thanks guys.

 

5K is about all I get with towing.


You can get upwards of 7K non towing.


On the information screen is where I think it is.

 

......and Synthetic Oil will mix perfectly fine with Non-Synthetic..... The only real difference between the two is that Synthetic is pure (well mostly - that's another subject) without "inert ingredients, byproducts" etc..
Don't worry about mixing them.

 

[QUOTE=senix;15683508]I would not add at all till you get the 200 miles till empty.


While you can add it anytime the system works best by running it down and then giving it a complete fill up.

Why is it better to run it down? Is it just to keep the DEF fresh?

 

[QUOTE=senix;15683508]I would not add at all till you get the 200 miles till empty.
While you can add it anytime the system works best by running it down and then giving it a complete fill up.

Why is it better to run it down? Is it just to keep the DEF fresh?

 

It's better to let it run down because the computer resets your DEF usage. Since there is not a float in the DEF tank on the truck. There are only 3 sensors to determine your DEF level.

I haven't had a problem refilling at 1/2 full or sometimes higher, but apparently some people have gotten the countdown because they always keep the DEF tank topped off and then they are full of DEF, but still can't drive the truck.

Everything else has been answered the same way I would answer it regarding mixing oil and such.

 

I just received the "500 mi.DEF message", just about 10,000 mi. since my last fill-up/oil change.
As noted above you can go to your info screen and select DEF, it will tell you where you are at.

 

Once mine hits 500 miles to empty I get the message at every startup and you have to click OK to clear it each time. I go through quite a bit of it since over half of my miles on the truck is towing heavy. My truck odo is at about 32k. My trailer odo is at about 19k.

 

Well that's good to know. I just wanted to make sure I wasn't miss the notice to refill the DEF tank. After all the reading I do on this forum, I'll just wait until I get the notice before I add any.
Thanks guys