LaRed

Because I don't want the inconvenience of stoping/hunting for a place to buy it and sorting through a pile of boxes to be sure I buy DEF that is in date. Other than that I guess you're correct..

I took mine in for excessive use of DEF. My post is on earlier on this thread for details. Chevy said they reprogramed to hopefully improve but gave me a written explanation telling me to expect high usage while towing. I was back at the dealer today (my truck lurches into gear upon restart after sitting at a light. Im told this is a 2 day fix after waiting almost 3 months for the part) and they asked if my DEF usage has improved under load. I can't answer because I have not had an occasion to tow anything more than a few miles. Apparently,, now there is a recall notice for excessive DEF usage with the 3.0 Duramax. I hope this greatly improves because it is definitely excessive while towing. I don't think I should be expected to load up 7 1/2 gallons of DEF in the bed for a 1500mi round trip while pulling a 3957lb (I know cause I weighed it) boat, motor, trailer loaded with fishing gear. I really like this truck but this issue adds another headache and makes it a poor cost, benefit relationship. This will not be a long term marriage if this is normal.

My issue, though not exactly like yours was close enough to call the same. Gauge or computer needs reprograming. And they seem to use an incredible amount of DEF when pulling a 4500 lb load. This is very disappointing to me. Never thought I would use my truck bed to haul DEF when on a trip pulling my flats boat.

It is the Magnuson Act, Passed by Congress December 17, 1943. They have the right to write specifications but not require consumers use their brand. Where you going to find an open GM dealer at midnight anywhere if you need DEF.? If this is the case my brand new truck will belong to someone else shortly.

delete

Bought late January. I have 5700+ mi on mine. DEF tank full when I left the dealer. First 4300 mi. DEF gauge showed 1/2 tank remaining. No towing practically all highway mi. Thought I should have plenty to make a 1250 mi trip home from FL pulling my 20 ft Flats boat based on history. After 200mi. DEF warning 1000 mi remaining still only 1 bar under 1/2 tank. 2 1/2 gallons of Blue DEF from WalMart put it back to 1 bar under full. 50 mi from home warning came on again.... 265 mi. remaining. This was shocking. Another 2 1/2 gallons of Blue DEF from WalMart put the gauge back to 1 bar under full. So..... not sure how much I'm burning. But I do expect the gauge to be more accurate. This does seem to be excessive to me. Maybe its not. Based on the gauge it seems certain I burned at least 2 1/2 gallons in 1000 mi. while pulling the boat. Overall fuel mi including the tow home 21.3. Towing the boat only ..15.1 for the 1250 mi. trip to NW Arkansas. Overall before towing 22.7.