Am I just being paranoid

CowboyCVW

Member
Joined
Aug 26, 2017
Location
Texas
TDI
2015 Jetta SE TDI
so I have had my 2015 jetta TDI since august. At first I was a bit concerned as MPG was lower than expected but i found the car does better in cooler outside temps. Fast forward now and im finding that once outside temp is above 95 my jetta is running sluggish on acceleration,and im all of the sudden struggling to get 40 mpg at best on my daily 100 mile highway drive. Judging by the 1000rpm idle the car seems to be going into regen more often and if I shut down when I get home the fan is running. Changing the air filter last night I went check the dipstick and immediately smelled diesel. I know soot and a little fuel can get in the oil on a diesel but comparing to my ford powerstroke its never that noticeable.

Im curious if I should be concerned here. Anyone else with a Mk6 post fix vehicle seeing degraded performance and MPG in hot outside temps?
 

iamatt

Veteran Member
Joined
Apr 5, 2006
Location
Rosharon, Texas
TDI
2014 Jetta 6 Speed manual
Straight pipe and tune. Get rid of that vw fix software and enjoy the car.

Sent from my FRD-L14 using Tapatalk
 

CowboyCVW

Member
Joined
Aug 26, 2017
Location
Texas
TDI
2015 Jetta SE TDI
Straight pipe and tune. Get rid of that vw fix software and enjoy the car.

Sent from my FRD-L14 using Tapatalk

Im at least going to let the factory warrant run out first before i start modding the car. Are there any 2015s deleted that have anought mileage out there to know if this build will hold longevity like past cars? that 12 year 162K warranty is the other thing that has me hesitant to delete.
 

tdi54

Veteran Member
Joined
Dec 19, 2010
Location
California
TDI
1981 Rabbit Diesel(sold), 2009 Jetta TDI MT(sold)2010 Jetta TDI MT, 2015 Jetta TDI SEL, DSG, 99 Ford F 350 PSD Dually, 2016 BMW X5 xDrive35d, 2016 535d
Something is not right. 2015 TDI's are quite
efficient. Without trying you should get upwards of 40 miles if not more. I have bought mine in March 2018 and did not
experience FE reduction in hot weather.Mine does regent at about every 250 miles I think. If yours is more often than this interval, that may need to be looked into.
I wish I could help you, hopefully other members will chime in.
 

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
if I shut down when I get home the fan is running.

My Passat will have the fan running if I shut the car off during a regen cycle. But I have a Scangauge II plugged into the OBD II port and have two gauges that tell me the temperature of the exhaust. If I see it is 1,200 or so degrees I wait with the car idling until the temperatures are around 400 deg before I shut down. Only takes a few minutes.

If you shut down during a regen cycle it will do that when you restart again.
 

goodmonkey

Veteran Member
Joined
Mar 20, 2006
Location
Anchorage, AK
TDI
2014 Passat TDI, 2011 Touareg TDI
I'm using VAG DPF app and it seems I'm going through a regen every 250 miles or so with my '14. In the afternoons however the fans are running quite often when I shut down, but it isn't EGTs or DPF temp that are causing it, rather the coolant temp is 218F or so as read through Torque. Things are just that hot.

While VCDS is a great tool with smartphones it is worth having a Bluetooth OBDII scanner (mine was about $20 IIRC) to help answer some quick questions like these before taking it in or grabbing the VCDS and laptop out.
 
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forrest resto`s

Veteran Member
Joined
Jul 8, 2007
Location
athens ga.
TDI
2000 jetta tdi auto rc2 2013 passat tdi 2015 passat tdi auto 2011 jetta tdi nav. s'roof..man. dpf delete 1970 GTO JUDGE 520 HP
I'm somewhat confused.. all the 40+ mpg's claimed.. is anybody saying this is strictly hwy. careful driving miles?? I hope y'all will be more definitive in your "mpg's" cause I really believe most people aren't getting 40+ mpg's just driving around...Thanx for clearing this up for the "novice's"... I have 4 of these tdi's.. and you if you drive these like most drive their "Honda's or Toyota's" you will not get 40+...
 

CTD_Chevrolet

Veteran Member
Joined
May 31, 2011
Location
Montucky
TDI
'15 Jetta S DSG, '02 Jetta ALH 5spd
I'm somewhat confused.. all the 40+ mpg's claimed.. is anybody saying this is strictly hwy. careful driving miles?? I hope y'all will be more definitive in your "mpg's" cause I really believe most people aren't getting 40+ mpg's just driving around...Thanx for clearing this up for the "novice's"... I have 4 of these tdi's.. and you if you drive these like most drive their "Honda's or Toyota's" you will not get 40+...
I get garbage mileage in town but yeah highway I get 45-46 consistently. My highway low is ~41 and that's only happened a couple times. When it's under 44 I start wondering what's going on. City, on the other hand, is all over the place, high 20s to low/mid 30s, which I partially attribute to aggressively massaging the throttle to mitigate the emissions/dsg tuning.
My highway speeds are 70-80 depending on where I am. Most of the miles are driving between southwest MT and the bay area in CA. I've broken up the drive different ways to see how much of a difference terrain makes but I haven't noticed any big differences. I keep telling myself I'll figure out how much speed influences it but every time I decide I'd rather get there an hour earlier than find out. :D

Edit:
I have one high temp datapoint: 547 miles from Wells NV to the north bay, 44.92mpg 95+ degrees AC cranked the whole way (paraphrasing the note I took). Most of that would be 70-80 slowing down in the end but going through rougher terrain.

Edit 2:
I got confused and thought I was applying to OP but my comment is relevant to both
 
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NewYorkBuck

Veteran Member
Joined
Jul 24, 2005
Location
NY/NJ metro
TDI
Jetta 2015 Black
I'm somewhat confused.. all the 40+ mpg's claimed.. is anybody saying this is strictly hwy. careful driving miles?? I hope y'all will be more definitive in your "mpg's" cause I really believe most people aren't getting 40+ mpg's just driving around...Thanx for clearing this up for the "novice's"... I have 4 of these tdi's.. and you if you drive these like most drive their "Honda's or Toyota's" you will not get 40+...
I have a 2015 with over 80k. On the highway, I get 48-49, hand calculated. Around town and highway mix, I get 42-44.

I calculate my mileage almost every tank, and I have never carded below 40.
 

chaoscreature

Veteran Member
Joined
Sep 10, 2007
Location
vista, ca
TDI
2006 Jetta TDI Special Edition
Is no one else concerned about the heavy diesel smell in his oil? My oil is gross black immediately on my mk5 and mk6 tdi, but has never smelled like diesel.
 

tdiinsc

Active member
Joined
Feb 28, 2018
Location
Greenville, SC
TDI
2015 Golf Sportwagen TDI, 14' Jetta TDI
so I have had my 2015 jetta TDI since august. At first I was a bit concerned as MPG was lower than expected but i found the car does better in cooler outside temps. Fast forward now and im finding that once outside temp is above 95 my jetta is running sluggish on acceleration,and im all of the sudden struggling to get 40 mpg at best on my daily 100 mile highway drive. Judging by the 1000rpm idle the car seems to be going into regen more often and if I shut down when I get home the fan is running. Changing the air filter last night I went check the dipstick and immediately smelled diesel. I know soot and a little fuel can get in the oil on a diesel but comparing to my ford powerstroke its never that noticeable.
Im curious if I should be concerned here. Anyone else with a Mk6 post fix vehicle seeing degraded performance and MPG in hot outside temps?
Granted i dont have much experience in the TDI world, but mine with phase 2 fix started to regen more than my wifes golf sportwagen (hers with phase 1 only). I noticed that if once a day i really give it the beans it reduces the amount of regens. Mine would typically be in a regen cycle the minute i got home from work. After adjusting how i drive it, i havent noticed it at all.

Someone correct me if im wrong, but regens will occur when the soot level in the DPF reaches a certain level. Driving the car easy may contribute to more frequent regens. Its possible that the threshold was lowered to encourage more regens to save the DPF from getting clogged up. Sorry if my frequent use of the regens is annoying :)

Oh yeah forgot to add, its hot as balls in Greenville.....typically at least 95 every day when i drive home from work.
 
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