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Discussion Starter #1


I was reading @AnywhereInTX 's review of the 2015 Ram EcoDiesel, which is really well done by the way, but I didn't know much about diesel exhaust fluid (DEF) which he mentions as his one complaint at the end of his review. Here is what he had to say about it:

One thing that I am noticing is the rate at which this truck consumes DEF. Ram claims that the 11 gallon tank is designed to last 10,000 miles, that way the oil change and DEF fill can be done at the same time. However, I currently have 1600 miles on the truck and I am close to the 1/2 tank mark.
I decided to do some research on both what DEF is and if there is something fishy going on with the Ram EcoDiesel's consumption of it.

DEF is a fluid that is now required by the EPA. If a diesel vehicle runs out of DEF then the EPA mandates that the engine must disable. So its a pretty important part of your truck.

DEF reduces your engine downtime, maximizes fuel efficiency, and provides more O2 for efficient combustion. Through the use of DEF, nitrogen oxide emissions can be reduced to near 0. To sum that up, DEF reduces emissions and improves your engine's performance.

Ram says that the DEF tank should last for around 10,000 miles so that you can refill it at the same time as you change your oil. @AnywhereInTX says that his tank was at about a hlaf at just 1,600 miles, so something has got to give here.

There are two things I would bring up to solve this quandary. First, I am curious how accurate the gauge is for the DEF. Sometimes companies purposely make gauges less accurate so that people won't wait till the last minute, or until its too late, in order to do necessary maintenance. You could actually take a look inside the tank, if that's possible, to see if it actually looks like it is 1/2 full.

Second, towing and how you drive could affect the rate at which the DEF is consumed. @AnywhereInTexas was towing 6,000 lbs during his first jaunt in the Ram EcoDiesel. That extra weight could also be to blame.

All in all I think we have it pretty good though. The Silverado 2500 also uses DEF, but its tank is only supposed to last 5,000 miles between refills. So I think that the Ram 1500 EcoDiesel is doing pretty well for us when it comes to its DEF system.
 

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I made a trip to northern Michigan a couple of weekends ago. On the return trip home, I decided to top off the DEF tank. I stopped at Pilot Flying J since they have DEF at the pump for $2.799 a gallon. After 1800 miles, the tank required 1.67 gallons of DEF. Assuming my algebra is correct and if we could use all 8 gallons (in theory), I calculated an 8600 mile range. This was for approximately 65% city driving and no towing.
 

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DEF also is consumed at a higher rate the high your RPMs go. So if you like to drive hard you use more DEF, just like fuel...
 

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Discussion Starter #4
It seems pretty clear that the rate at which the DEF gets used up does have to do somewhat with the way you drive your Ram 1500. So its not simple inaccurate numbers from Ram. Though companies usually tend to wards the nicest version of their data when they are releasing figures.

The most important thing is to just make sure that you have some extra DEF in the trunk or you fill it up regularly because you don't want to see what happens when you run out.
 

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Nice post. One thing I have noticed is now that the truck isn't being experimented on (by me for review purposes) and is back to just daily driving duty, DEF consumption has slowed down. Whether it was system break in or high consumption rate due to towing, this thing can eat some DEF. Either way, like some have posted DEF can be purchased at truck stops for cheap so I'm not worried too much. Just was surprised that Ram claims 10k miles, but I will probably make it to about 7-8k miles with it.
 
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Mine was a little over 3/4 when I bought new not quit full got down to close to 1/8 no low light or anything came on had 7300 miles on it have only pulled 16' utility trailer couple times
 

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DEF consumption accuracy




Ram says that the DEF tank should last for around 10,000 miles so that you can refill it at the same time as you change your oil. @AnywhereInTX says that his tank was at about a hlaf at just 1,600 miles, so something has got to give here.

I just passed the 2,500 mile mark on the odometer and the DEF gauge reads 3/4 tank. For me it's spot on. I'm 50% city & 50% highway, don't tow, and livin in CA means doing 75-80 is normal. So even with the higher revs on highway, it's pretty accurate... This post has been quiet for a while, but thought I would chime in.
 

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I ran out a couple times this winter well the def was froze and the gauge never moved the whole time so I'm assuming it run out then it warmed up to just under the freezing mark and the gauge dropped to zero, warning came up so I had some with me and put it in. Did I run out? Was the engine not getting any for a long time? I idle it a lot because of my job, it used a lot idling so I would throw some in every once in a while because the gauge never moved from 1/4.
Randy
 

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I added my first yesterday as it was getting close to the red line. It was a bit under the 3/4 full mark when I got the truck, and I have only put 1300 miles on it since I got it. I don't drive it hard and don't idle it much. About 3/4's of the miles I put on were highway. This is a far cry from the 10,000 miles that Dodge state. It cost $14.68 Cdn taxes in for 2.5 US gallons.
 

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That is very odd, I just bought a new 2017 and started with a full DEF tank, have 1300 miles on it, and just barely below the full tank mark.
 
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