The owner's manual says my truck has a 5.5 gal DEF tank. I waited until I was down to 1/4 on the gauge, just above the red zone, and added a 2.5 gal box of Blue DEF from Advance Auto. Now the gauge reads FULL to the top.So the gauge must be set to give you a long warning zone to keep you out of limp mode. This is only my 2nd time adding DEF so just getting used to all of this.Also interesting is that the DEF I got said "Blue DEF" but the Peak brand is gone, and so is the manufacture date. No date or code of any kind on the box or the container so no way to know how old it is. With tax it was $15 for 2.5 gals, so $6/gal. Probably last time I'm buying it at Advance.

BurbMan wrote:The owner's manual says my truck has a 5.5 gal DEF tank. I waited until I was down to 1/4 on the gauge, just above the red zone, and added a 2.5 gal box of Blue DEF from Advance Auto. Now the gauge reads FULL to the top.So the gauge must be set to give you a long warning zone to keep you out of limp mode. This is only my 2nd time adding DEF so just getting used to all of this.Also interesting is that the DEF I got said "Blue DEF" but the Peak brand is gone, and so is the manufacture date. No date or code of any kind on the box or the container so no way to know how old it is. With tax it was $15 for 2.5 gals, so $6/gal. Probably last time I'm buying it at Advance.The Walmart house brand is about $9 and it is just a generic chemical that most people seem to think makes all brands equal.

Buy from the pump at truck stops. Not only is it fresh and stored in a cool place to last longer, but is also only costs about $2 per gallon.My dealerships sells DEF. I can tell you that most of it sits out in a hot warehouse or in a hot semi-trailer for ages before being put out in the showroom which lowers the shelf life.

DEF is an aqueous urea solution made with 32.5% urea and 67.5% deionized water.Brand shouldn't matter

Groover wrote:BurbMan wrote:The owner's manual says my truck has a 5.5 gal DEF tank. I waited until I was down to 1/4 on the gauge, just above the red zone, and added a 2.5 gal box of Blue DEF from Advance Auto. Now the gauge reads FULL to the top.So the gauge must be set to give you a long warning zone to keep you out of limp mode. This is only my 2nd time adding DEF so just getting used to all of this.Also interesting is that the DEF I got said "Blue DEF" but the Peak brand is gone, and so is the manufacture date. No date or code of any kind on the box or the container so no way to know how old it is. With tax it was $15 for 2.5 gals, so $6/gal. Probably last time I'm buying it at Advance.$7.88 in my area and that's all I use. The pump Def is cheaper but not convenient in my area. The Walmart house brand is about $9 and it is just a generic chemical that most people seem to think makes all brands equal.

Blue is $10 at Costco and that's what I've been buying lately because it's the most convenient. It's only a buck a gallon more than buying it at the pump.

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Lantley
Nomad
Nov 25, 2020
You Ram/Dodge guys are fortunate enough to have a decent place to fill your DEF and maybe even gauges!
The fill for my Chevy is under the hood and there is no gauge.
I try to fill at the pump just because its much easier than filling from the box under the hood
IdaD
Explorer
Nov 25, 2020
Blue is $10 at Costco and that's what I've been buying lately because it's the most convenient. It's only a buck a gallon more than buying it at the pump.
Ron3rd
Explorer III
Nov 25, 2020
Groover wrote:
BurbMan wrote:
The owner's manual says my truck has a 5.5 gal DEF tank. I waited until I was down to 1/4 on the gauge, just above the red zone, and added a 2.5 gal box of Blue DEF from Advance Auto. Now the gauge reads FULL to the top.

So the gauge must be set to give you a long warning zone to keep you out of limp mode. This is only my 2nd time adding DEF so just getting used to all of this.

Also interesting is that the DEF I got said "Blue DEF" but the Peak brand is gone, and so is the manufacture date. No date or code of any kind on the box or the container so no way to know how old it is. With tax it was $15 for 2.5 gals, so $6/gal. Probably last time I'm buying it at Advance.

$7.88 in my area and that's all I use. The pump Def is cheaper but not convenient in my area.

The Walmart house brand is about $9 and it is just a generic chemical that most people seem to think makes all brands equal.
Old-Biscuit
Explorer III
Nov 25, 2020
DEF is an aqueous urea solution made with 32.5% urea and 67.5% deionized water.

Brand shouldn't matter
ShinerBock
Explorer
Nov 25, 2020
Buy from the pump at truck stops. Not only is it fresh and stored in a cool place to last longer, but is also only costs about $2 per gallon.

My dealerships sells DEF. I can tell you that most of it sits out in a hot warehouse or in a hot semi-trailer for ages before being put out in the showroom which lowers the shelf life.
Groover
Explorer II
Nov 25, 2020
BurbMan wrote:
The owner's manual says my truck has a 5.5 gal DEF tank. I waited until I was down to 1/4 on the gauge, just above the red zone, and added a 2.5 gal box of Blue DEF from Advance Auto. Now the gauge reads FULL to the top.

So the gauge must be set to give you a long warning zone to keep you out of limp mode. This is only my 2nd time adding DEF so just getting used to all of this.

Also interesting is that the DEF I got said "Blue DEF" but the Peak brand is gone, and so is the manufacture date. No date or code of any kind on the box or the container so no way to know how old it is. With tax it was $15 for 2.5 gals, so $6/gal. Probably last time I'm buying it at Advance.

The Walmart house brand is about $9 and it is just a generic chemical that most people seem to think makes all brands equal.

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