DEF question

[JASONP]

I don't have to purchase any DEF as of yet due to the first fill being free with oil change but... in searching I can only find one product with a temp rating of -12°C which it does get colder here and concerned about freezing
Any suggestions?

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[40X40]

The engineers thought of that and addressed the issue. How do you think they solved the problem?

Bill

 

[FreezingInSask]

All DEF freezes at or around that temp. And due to that fact it needs to maintain 32.5% Urea and 67.5% de-ionized water, they cannot just add anti-freeze to solve this problem. I haven't read much on exactly how VW solves this, but I'm sure it's not much different than how the truck companies do it. They use electric heaters around the lines which are purged after the car is shut off to prevent freezing in the lines. They then pump engine coolant to heat and melt the DEF in the tank.

 

[JASONP]

I inquired at the dealer this morning and asked about their Ad Blue which is rated at -11°C, the lines are heated to prevent freeze ups and the volume of the tank prevents that from freezing

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[JASONP]

The engineers thought of that and addressed the issue. How do you think they solved the problem?

Bill

Well Bill, not having a urea injection system before I'm learning in advance prior to any issue.
I have read in here some owners of Passats having freeze ups with theirs.

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[40X40]

You figured it out!
There were some heater failures early on, and VW had to replace a few.

Good job.

Bill

 

[VeeDubTDI]

VW (and other manufacturers) use extensive use of electric heat.

The tank is heated, the pump is heated, and the lines themselves are heated.

When the engine is turned off, all of the fluid that was in the lines is pumped back to the tank so that it can't freeze in the lines.

If you read the 3.0 TDI self study program, it explains the AdBlue system in great detail.

 

[JASONP]

You figured it out!
There were some heater failures early on, and VW had to replace a few.

Good job.

Bill

Usually do thanks to vdub for the extra clarification. My question was about DEF and what brand was rated lower then -12 not about how the system works but thank you Bill for your input.

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[Windex]

None of them are rated much below -12c, it''s just the nature of the beast. On the truck side, we make sure that all of the heater circuits are working, and when filling, make sure that you get DEF which is a fresh as possible. It goes stale over time, and loses effectiveness and starts to freeze earlier.

We have bulk DEF dispensers at most of our locations, and they are all in heated enclosures.

 

[JASONP]

None of them are rated much below -12c, it''s just the nature of the beast. On the truck side, we make sure that all of the heater circuits are working, and when filling, make sure that you get DEF which is a fresh as possible. It goes stale over time, and loses effectiveness and starts to freeze earlier.

We have bulk DEF dispensers at most of our locations, and they are all in heated enclosures.

And now i know thanks Adam
Seems the average is -11/12
Was hoping to find something lower but oh well que sera...

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[VeeDubTDI]

Usually do thanks to vdub for the extra clarification. My question was about DEF and what brand was rated lower then -12 not about how the system works but thank you Bill for your input.

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The answer is none. They all freeze at the same temperature due to the chemical makeup requirements of the fluid.

 

[dubStrom]

Traded my 2013 Passat for one of the last of the 2014 JSW TDIs. No telling when the 2015 urea injected models will show up. I did not have any trouble with my urea system in the Passat. But urea free TDIs are about to become extinct, and I can't get a Passat wagon.

Just one less system to fail and need diagnosis and fixing. These cars are getting more and more complicated!

As long as the heaters continue to heat, it should work just fine. But the idea that the "volume in the tank" will prevent it from frezing is not completely true. It gets cold enough, the entire tank will freeze. It creeps in from the surface, just like an ice cube tray. But the heater should get enough going to keep it working. not much is needed to feed the system, and the heater is integrate with the pump (which makes it an expensive replacement part!).