DEF Fluid - Chevy and GMC Duramax Diesel Forum

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post #1 of 18 (permalink) Old 08-29-2011, 05:19 PM Thread Starter
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DEF Fluid

Looking at getting a 2011 duramax and saw the requirement to change DEF fluid every 5,000 miles. What is DEF fluid and how much does this cost? I love my Duramax, but damn another fluid to change.

2002 2500 Crew Cab Duramax
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post #2 of 18 (permalink) Old 08-29-2011, 09:38 PM
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I thought you added more.

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post #3 of 18 (permalink) Old 08-29-2011, 09:40 PM
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You dont change it, it is for emissions and used up in use of the vehicle.

I actually seen it for sale at walmart here last week.

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post #4 of 18 (permalink) Old 08-29-2011, 09:47 PM
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Price varies where you buy it, it is used in the exhaust to treat emissions. Mileage varies depending on different variables like driving conditions.

Like mentioned it's a fluid filled up, not changed.

DEF isn't a bad thing. LML has good power and fuel mileage with a warranty.

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post #5 of 18 (permalink) Old 08-30-2011, 05:00 AM
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DEF is a sacrificial fluid but it does have a shelf life of about one year. If you don't use it, you have to change it.
You can buy urea ( DEF fluid ) at most Pilot Travel centers at the pump and many parts stores....I sell it in half gallon bottles with a quick disconnect cap.
DON"T buy it from the dealer....they are marking the price up X10.
If you are pulling out on the highway a lot and not just poking around town, a urea fill will last for 10,000 plus miles between fill-ups
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post #6 of 18 (permalink) Old 09-08-2011, 08:21 AM
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Tis a shame GM decided not to put a level indicator on the DEF reservoir. :/ am sure I read somewhere a % level is obtainable thru a scan tool(tec2 etc) but not 100% on this. Have considered fabbing up a dipstick to be able to randomly check the level, but again, with the possibility of contamination(which shows up on the DIC as poor quality DEF fluid) am yet to give it a shot. Ideally it would be a length of plastic, similar to whats found in between yella-tung flooring. currently using a brand known as Nonox, which states not to allow contact with any metal as cross contamination occurs.

Come on GM, give us an update for the DIC for the DEF level!!!
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post #7 of 18 (permalink) Old 09-11-2011, 03:14 PM
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Does anyone know the actual milage you can go before adding fluid? I currently have about 4000 miles on my LML and have not added any fluid yet. I leave for an elk hunt this coming Sunday and was wondering if One Gallon is going to be enough or do I need to purchase more? I've really been babying it since I got it, with no towing yet and not getting on it.

Peenutt: 2011 LML Chevy Durfamax, Taupe Gray and stock for now.

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post #8 of 18 (permalink) Old 09-11-2011, 03:20 PM
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I'm at 5000 miles and according to my insight i still have over 60% left in the tank!!

also check this out:

2011 Chevy LML. No DEF for me.
I got tint and tires but i'm not telling what % or what size......
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post #9 of 18 (permalink) Old 09-11-2011, 03:44 PM
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I think I filled mine about 9-10k dont remember. Dont worry about it until the 1k warning comes on.

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post #10 of 18 (permalink) Old 09-11-2011, 04:10 PM
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DEF will last between 10k and 13k miles for most depending on driving conditions. The book says 5k but we are getting much more.
Don't sweat'll get a warning well before you are out.
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