DEF

[dennis1949]

On my 2012 GMC, when do you add def to it. It has 7000 miles on it and the dash still says it is ok. How many miles can I go before I can exoect to add any?

[Rob & Cathy]

The rule-of-thumb seems to be about 1000 miles per gallon of DEF. I don't know how big your tank is but I'd add DEF just to see how much it took.

Rob

[Travelers]

I've never seen an ADD or Low DEF message in my truck. I add a gallon every month or after every two regens.

[Mike Clay]

You are probably getting pretty low. Yes about 1,000 miles per gallon as Rob says and around 750 mpg while towing. Dont wait for the message to come on put a few gallons in it or fill it if you are not going to get any freezing weather.

[LuvRving]

I hate to ask this but what is a regen.? I've seen the term in several posts and I'm curious! I have had my 2012 diesel for a year now. I add about 3 to 4 liters every 1000 km or so.

[Rob & Cathy]

A regen is when your truck dumps some fuel down the exhaust to turn your DPF into a self-cleaning oven. I don't know if applies to Canada.

Rob

[Mike Clay]

Actually Joe if your truck does regen it has a 9th injector in the exhaust and works like Rob said, a self cleaning oven. You will notice regen when your idle is elevated when the truck is warm since in your case I am sure you have the high idle turned on for your area when the truck is cold.

[dennis1949]

I called the GMC dealer here and talked to the service manger. He said usually between 7500 and 10000 mies before message on dash says to add DEF. Book says do not fill up till warning on dash comes on but it would not hurt anything to top it off before this

[Mike Clay]

Dennis it is hard to judge, sometimes you can go to what seems forever then all of a sudden you start getting messages. I guess unless I am traveling I just have the dealership fill it when I come in for an oil change. I know towing I use 2 1/2 to 3 gallons for every 2,000 miles. I have never seen the message come on in mine so I dont go by it, I can see on my Edge Insight when I am down to about 2 gallons. And that is only because it goes from 100% to 55% when I take off from a signal. When that happens i put another 2 gallons in.

By the way 10,000 miles? , maybe.

[JimOMartin]

I have a 2011 Chevy Silverado. Do you guys actually get some type of messages indicating DEF level or just when it gets low? I've never seen anything related to DEF. I have been filling it up every now and then but wasn't sure what type of messaging I'd get from the truck.

- Jim

[Mike Clay]

You will get a message that say you have 1,000 miles to go, if you ignore it you will eventually get a message that says wake up or I'm going into limp mode at 5mph

[Mike Clay]

I use this

From here
Edge

[jtaylor1920]

The Edge Insight is a fantastic tool and I use it to alert me when my regen starts and finishes. Some brilliant engineer at Ford decided to remove the alert tone that used to sound when a regen started in one of the flash updates. Without the Edge I had to monitor my mileage constantly and listen for the idle change to know it started. Mike, it looks like the GMC tells you how close you are to a regen......that is a nice feature.

[Rob & Cathy]

Some brilliant engineer at Ford decided to remove the alert tone that used to sound when a regen started in one of the flash updates.

That works for me John. I would prefer they got rid of the message that pops up on the display saying that regen has started. The only messages that should pop up are warning and things I need to take care of.

Rob

[Gary & Misty]

Don't know about the regen...I'll have to read the manual. My new Ram has a DEF gauge just like the fuel gauge. Haven't found what the tank size is yet, but I was about 1/4 or so and put about 4 1/5 gal in yesterday. My motor home has a 13 gal DEF tank.