# Which "DEF" to use.



## Joe Hittle (Jul 26, 2018)

The fill-cap on my Cruze indicates that it is to be fed "blue DEF."

I'm seeing other posters here indicating that they are using truck-stop-pump DEF.

Is there ANY reason (other than GM hype) to specify "blue DEF" rather than the truck-stop "stuff?"


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## MP81 (Jul 20, 2015)

Anything sold as "DEF", legally, has to meet the same criteria, otherwise it cannot be sold as DEF. 

You can use any kind of DEF you like - many people here fill up at the truck stops.


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## 91794 (Mar 25, 2015)

Its the same stuff. Its not really blue. 
Daimler benz started the whole blue terminology for diesel emissions stuff, if i recall correctly. Their engineers really are comprehensive and probably also have a working method in their back pockets to reduce diesel emissions using blue balls. Or maybe that would be in their front pockets.


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## LiveTrash (May 24, 2015)

As said, anything DEF will work. Just be mindful of where it's stored. Sometimes gas stations will leave it out in direct sunlight which over time can spoil it. Freezing temperatures too will also cause it to go bad while it is being stored before use. The DEF system can be a sensitive one and needs to be fed with properly stored fluid.


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## crunch21 (Jul 16, 2018)

curious what if you just used tap water? i get it needs the ammonia for the chemical reaction but in a pinch could you just dump some water in the tank and be ok? Dont own the oil burner but ive always wondered if the thing knows if your using real DEF


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## LiveTrash (May 24, 2015)

crunch21 said:


> curious what if you just used tap water? i get it needs the ammonia for the chemical reaction but in a pinch could you just dump some water in the tank and be ok? Dont own the oil burner but ive always wondered if the thing knows if your using real DEF


As I posted, yes, it's a very sensitive system. It will know almost immediately that there is "bad DEF" in the system and will shut itself and eventually the entire car down to avoid damage.


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## Chris Tobin (Feb 23, 2016)

There was a chase truck for the Baja 1000 in 2012 stuck in Guerrero ***** (a little more than half way down the Baja peninsula that had a DEF tank issue and they tried water and I think even Pee'd in the tank but the truck shut them down and went into limp mode allowing only 15 MPH even after they got to a town that had DEF and drained and filled it with proper DEF. I think they had to have the truck towed to Ensenada or even all the way stateside for a Chevy dealer to flush and service the system.

The morals of the story: 1) If you are traveling in areas where you suspect there may not be DEF available bring extra with you!!! 2) DO NOT put anything other than DEF in the DEF tank!!!


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## pandrad61 (Jul 8, 2015)

the easiest and most cheap way is go to a big rig fuel station and pump it in. this way you dont have any left over, less chance of spill due to a nozzle, and cost is cheapest per gal.


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## IndyDiesel (May 24, 2015)

With my gen 1 diesel I can go about 20000 miles on a full tank of DEF. so I don’t add very often


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## Joe Hittle (Jul 26, 2018)

Thanks guys!!

The reason I asked has to do with needing to change a NOX sensor which flagged the check-engine light last weekend. The dealership changed the sensor under warranty, and didn't say anything at all about the DEF system.

But, I wondered. I've used the "big-boys" pumps a couple of times and was very much hoping that doing so wasn't the cause of this, and the other "issues" I've described in another thread.

Again, Thanks everyone!!

Joe


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## Joe Hittle (Jul 26, 2018)

IndyDiesel said:


> With my gen 1 diesel I can go about 20000 miles on a full tank of DEF. so I don’t add very often


What sort of fuel-mileage are you getting with your Gen-1? And, how is the front-end suspension holding up under the cast-iron block?

Having been around more than a few VW diesels from the late 70s/early 80s, I like the idea of a cast-iron block instead of the aluminum one I've got. I'm thinking of picking up a used 2.0 Cruze diesel with an automatic for my wife to drive on a regular basis.

Thanks!

Joe


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## LiveTrash (May 24, 2015)

Joe Hittle said:


> What sort of fuel-mileage are you getting with your Gen-1? And, how is the front-end suspension holding up under the cast-iron block?
> 
> Having been around more than a few VW diesels from the late 70s/early 80s, I like the idea of a cast-iron block instead of the aluminum one I've got. I'm thinking of picking up a used 2.0 Cruze diesel with an automatic for my wife to drive on a regular basis.
> 
> ...


I'll chime in with mine and say it's been great. I've only had the DEF tank heater go (replaced under warranty) and the EGR valve seized up once (also replaced under warranty with a revised part). Other than that, extremely reliable and a fun car to drive. I'm not too familiar with vehicle assembly, so not sure what you're referring to about the cast iron block. The suspension performs as it did the day I got it, almost 4 years and 68,000km ago. No knocking or weird noises or any sort. I'm in Canada with some rough roads.


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## LiveTrash (May 24, 2015)

Joe Hittle said:


> Thanks guys!!
> 
> The reason I asked has to do with needing to change a NOX sensor which flagged the check-engine light last weekend. The dealership changed the sensor under warranty, and didn't say anything at all about the DEF system.
> 
> ...


If it's a popular truck stop, which I imagine any of them would be, then you'll be fine with their DEF. It comes delivered in bulk on a tanker truck and is stored underground and temperature controlled in a tank. A lot of trucks on the road now use DEF and they consume it fairly quickly. The fluid wouldn't have any time to spoil between deliveries.


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## MP81 (Jul 20, 2015)

LiveTrash said:


> I'm not too familiar with vehicle assembly, so not sure what you're referring to about the cast iron block. The suspension performs as it did the day I got it, almost 4 years and 68,000km ago. No knocking or weird noises or any sort. I'm in Canada with some rough roads.


The 2.0 LUZ has a cast iron engine block, while the new 1.6 LHZ has an aluminum block - diesels have always had iron blocks, so the switch to aluminum is a massive weight savings.


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## IndyDiesel (May 24, 2015)

Joe Hittle said:


> What sort of fuel-mileage are you getting with your Gen-1? And, how is the front-end suspension holding up under the cast-iron block?
> 
> Having been around more than a few VW diesels from the late 70s/early 80s, I like the idea of a cast-iron block instead of the aluminum one I've got. I'm thinking of picking up a used 2.0 Cruze diesel with an automatic for my wife to drive on a regular basis.
> 
> ...


Over almost 65000 miles I have a lifetime average of 43.9; do better in summer and worse in winter. The suspension is super tight. I have had very little issues, EGR stuck open once, took out and cleaned and it was fine, def tank heater replaced under warranty and have had recalls done and no other issues, extremely happy with the car. I drive mostly highway miles, I think that may contribute to a better experience. It is a heavy car for its size.


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