DEF usage?

Jetta_Pilot

Top Post Dawg
Joined
Apr 14, 2005
Location
West Hill, Ont.
TDI
2015 Passat Highline TDI Candy White (SEL Premium) long gone 2002 Jetta TDI
Just out of curiosity, I just did an almost 4,500 mile trip and today I thought I'd see how much DEF I used.
It barely took 1 litre or a bit more than 1 US quart.
That would mean it used way less than it ought to?
Any ideas why that may be?
 

Tom in PT

Veteran Member
Joined
Jun 7, 2017
Location
Twilight Zone, WA State
TDI
2005 Passat sedan - SOLD; 2013 Passat DSG; both purchased new
About 1-2 quarts per 5,000 miles is about what I am seeing for my 2013. Not much change at all from the pre-fix DEF consumption. IIRC the paperwork accompanying the fix indicated DEF consumption would increase substantially but that has not been the case for me. Not sure why that is either but otherwise the car is running normally.
 

Jetta_Pilot

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Joined
Apr 14, 2005
Location
West Hill, Ont.
TDI
2015 Passat Highline TDI Candy White (SEL Premium) long gone 2002 Jetta TDI
Like I said I was just curious, especially since I am now in Mexico and I force regeneration i.e run at highway speed in 4th gear.
Usually by the time I get home I add about 5-6 litres of DEF, which means that I use roughly 3 litres one way.
1 litre is slightly bigger than 1 US quart.
 

740GLE

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Aug 19, 2009
Location
NH
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2015 Passat SEL, 2017 Alltrack SE; BB 2010 Sedan Man; 2012 Passat,
Remember one of the goals of the ECU is to get the emissions systems and engine up to temp as soon as possible so I'd have to wager most of the def usage is during warm up. Under long highway cruises def usages is prob very very minimal as the increased EGR can help keep things cool and steady cruising speed has low EGTs, thus lower NOx without high DEF dosing.
 

Jetta_Pilot

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Joined
Apr 14, 2005
Location
West Hill, Ont.
TDI
2015 Passat Highline TDI Candy White (SEL Premium) long gone 2002 Jetta TDI
740GLE, I don't really want to argue the point, but on my twice yearly 2,500 to 3,000 mile drive I see my Scangauge EGT and CAT temperatures up in around 1,200° while I'm driving. Though it comes down fairly fast again. Normally it is around or under 500°.
 

740GLE

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Location
NH
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2015 Passat SEL, 2017 Alltrack SE; BB 2010 Sedan Man; 2012 Passat,
Right but during warm up in colder temps (which could take 5-20min) EGTs will be higher than normal operating temps (outside the times you catch a regen or climb a steap grade).


You're also a snow bird, how often do you warm up your car in 10-20F temps?

I'm not arguing just more of stating that with low ambient temps and short trips you will prob use more fuel and more DEF compared to a long highway run at 4-6hrs at a time.
 

hitman1985

Veteran Member
Joined
Apr 15, 2018
Location
Clarksville, TN
TDI
02 Jetta TDI ALH
I was wondering this same thing; bought mine with 112k on the clock now at 123 and had no refill prompts or anything so I'll hang on till she tells me to add some. It's clearly still got the rams urine because she reaks. Sad to smell that crap whenever I drive the passat vs I'd rather endure the alh diesel smell [emoji14]

Sent from my SM-G965U using Tapatalk
 

Quincy

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Joined
Apr 5, 2005
Location
Arlington, WA
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2015 Passat SE TDI, 2007 Dodge Cummins QC 4X4 6 sp, 2007 John Deere 3120
Like I said I was just curious, especially since I am now in Mexico and I force regeneration i.e run at highway speed in 4th gear.
Usually by the time I get home I add about 5-6 litres of DEF, which means that I use roughly 3 litres one way.
1 litre is slightly bigger than 1 US quart.
I'm pretty sure it has been mentioned that driving on the freeway in 4th gear doesn't force a regen. I have no idea. I don't even know when the thing is in the middle of a regen unless I turn the car off in the middle of it.

I'm in the middle of my own test, mostly because during my last service, I couldn't justify the $70 for them to fill the urea tank. I'm at 12,500 miles since the dealer last filled it. I'm 250-300 miles per week, mostly open freeway driving. My average MPG is right at 42 for the almost two years I've had the car.

Given my driving, anyone want to venture to guess at what mileage it will start telling me to fill that thing?
 

Tom in PT

Veteran Member
Joined
Jun 7, 2017
Location
Twilight Zone, WA State
TDI
2005 Passat sedan - SOLD; 2013 Passat DSG; both purchased new
Probably another 5,000 miles or more. Its not too big a deal to just get a jug of DEF, put lots of towels around the fill hole, and SLOWLY SLOWLY add DEF until it is filled to the brim. And then forget about it for a long long time.

If I were you I would do that, just so you know what your consumption rate is (filling it 1/2 quart at a time SLOWLY.)
 

Quincy

Veteran Member
Joined
Apr 5, 2005
Location
Arlington, WA
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2015 Passat SE TDI, 2007 Dodge Cummins QC 4X4 6 sp, 2007 John Deere 3120
I added once and found crystals on the trunk mat the next day. I certainly need to find a better way to fill it.
 

DivineChaos

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Jul 27, 2019
Location
Minnesota
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mk6 jetta sportwagen tdi
although i dont use def, my egt's are higher than normal now that winter hit. Although my mileage hasn't taken a huge hit it is burning more fuel to keep the dpf above 700f. my ash content is 45 on a 94k mile car. So i presume it was deleted and tuned when sold back. so i think the exhaust is new because the exhaust is spotless. also got it with 88k 2 months back.
 

740GLE

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Aug 19, 2009
Location
NH
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2015 Passat SEL, 2017 Alltrack SE; BB 2010 Sedan Man; 2012 Passat,
I'd be shocked that VW would invest in a new DP for a buy back and resell.
 

DivineChaos

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Joined
Jul 27, 2019
Location
Minnesota
TDI
mk6 jetta sportwagen tdi
I'd be shocked that VW would invest in a new DP for a buy back and resell.
maybe they brought it in with the car. or reinstalled it before the buy-back. think its likely that it failed and was replaced before the buy-back?
 

740GLE

Top Post Dawg
Joined
Aug 19, 2009
Location
NH
TDI
2015 Passat SEL, 2017 Alltrack SE; BB 2010 Sedan Man; 2012 Passat,
I got confused.

I thought it was taking of a Passat but the lack of def usage plus his signature states it's a JSW which is a CJAA, and those did get DPF replacements as part of the fix.
 
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