Winter MPG - how much decrease is normal?

digdug

Veteran Member
Joined
Jun 21, 2004
Location
vineland NJ
TDI
2013 jetta tdi
2013 6speed manual Jetta
for the past month I've been averaging only ~37mpg (commute is mixed driving, maybe 60-70% highway)

Prior to that I would average around 42-43mpg. Best tank I've ever had was around 46mpg (was in September).

Is that a normal hit to expect? Sometimes as much as I love the TDIs (I had a 2002 before this one), I think maybe a gasser econobox might have been a better value :(
 

peobryant

Veteran Member
Joined
Dec 5, 2014
Location
Kentucky
TDI
2010 Jetta TDI
I've only had my TDI for about a month (purchased it on December 10th, 2014) so I am by no means extremely knowledgeable on the TDI in general, however I have been driving a '91 Cummins since I was old enough to drive so I have experienced quite a few winters with diesel engines.

My TDI had previously been getting 44-45 mpg when the weather was in the 40's or so, the tank before last was actually my personal best at 47.5 mpg. Right after I filled up the temperature took a fairly extreme drop, going from mid 30's and 40's to 0 F and below in about a day or so. I filled up yesterday after driving with that temperature for the whole tank and without changing my driving habits or route, I dropped to 42.5 mpg.

I have consistently noticed drops in mileage when the weather gets extremely cold in my Cummins as well. I would go from averaging 20-22 mpg in my '91 dually to 16-18 mpg when the cold spells came.
 

digdug

Veteran Member
Joined
Jun 21, 2004
Location
vineland NJ
TDI
2013 jetta tdi
Thanks - I never noticed the drop in MPG on my 2002 , pretty much because it was an automatic :( and I never really kept a history on what it was getting for mileage. On that 2002 I'd base mpg if the car got at least 400mpg on a tankful. Even in winter that car would do that as lousy as that is for a ALH tdi.
 

Dannyboy

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Joined
May 25, 2013
Location
Mb
TDI
2014
Thanks - I never noticed the drop in MPG on my 2002 , pretty much because it was an automatic :( and I never really kept a history on what it was getting for mileage. On that 2002 I'd base mpg if the car got at least 400mpg on a tankful. Even in winter that car would do that as lousy as that is for a ALH tdi.
400mpg?
I'll have what he's having!

My bew drops 15-20% in winter almost like someone turned a economy switch to off.It's very noticeable.Thats more to do with the ecu putting in a extra bit of fuel to warm the engine up from 0F.
Im going to be installing a webasto which will help getting the engine up to heat lot quicker and will be able to see out my windshield for once
 

IndigoBlueWagon

TDIClub Enthusiast, Principal IDParts, Vendor , w/
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Aug 16, 2004
Location
South of Boston
TDI
'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
ALH's do lose FE in winter, but the newer cars lose more. They expend more fuel in warm up to heat up the emissions equipment quickly, and have more electrical losses (heated seats, electric cabin heater).

I find winter fronts on both cars help. I've been getting 46 pretty consistently this winter in my ALH driving mostly highway. My Golf on short trips in the winter will get around 40, whereas I see 43 or so in similar driving in summer.
 

digdug

Veteran Member
Joined
Jun 21, 2004
Location
vineland NJ
TDI
2013 jetta tdi
ooops!!!! I meant 400 miles for the tank I'd get
sorry I had too much 5 hr energy pre-gym workout when I posted that

400mpg?
I'll have what he's having!

My bew drops 15-20% in winter almost like someone turned a economy switch to off.It's very noticeable.Thats more to do with the ecu putting in a extra bit of fuel to warm the engine up from 0F.
Im going to be installing a webasto which will help getting the engine up to heat lot quicker and will be able to see out my windshield for once
 

RebelTDI

Veteran Member
Joined
Nov 1, 2009
Location
Boston, MA
TDI
2016 Audi Q5 TDI, 2016 BMW 535d Xdrive
Shorter commutes are much more affected than long, highway hauls, for obvious reasons. I am happy to say, though, that my diesel-guzzling 2010 CR TDI with snow tires on got 50 mpg on a trip from Boston to Philly down I95 with 4 people and luggage over the holidays. Driving around town, more like low 30s.
 

Mike in Anchorage

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Jan 4, 2009
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Anchorage, AK
TDI
2016 Touareg Lux, 2015 Golf Sportwagen SE, new 4 Sept 2017;2009 VW Jetta TDI Sportwagen (Ruby) sold to VW on 22 SEP 2017
You can make things best by being aware of your use of large electrical loads [are your side mirror heaters left on continuously?] and by blocking the front air flow. These are all good suggestions, and you'll make improvements by using them.

Fuel economy in winter is dependent on many things. Each state has its own standards for anti-gel additives by month and that impacts fuel economy, at least here in Alaska, by about 10 to 15%. Worst months are January and February. What a person gets in Arizona, Texas, and California will not begin to compare with effect you may see in upstate NY, Montana, or in Minnesota.
 

VeeDubTDI

Wanderluster, Traveler, TDIClub Enthusiast
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Jul 2, 2000
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Springfield, VA
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‘18 Tesla Model 3D+, ‘14 Cadillac ELR, ‘13 Fiat 500e
A 10-20% loss is normal in winter. Fuel economy will suffer more if you make shorter trips, as the warm-up is the big killer.
 

2.2TDI

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TDI
⠀⠀
A 10-20% loss is normal in winter. Fuel economy will suffer more if you make shorter trips, as the warm-up is the big killer.
This... I've seen a hit of up to 30% in the last month due to cold temperatures and mostly short city driving. Was getting 45-47 mpg a month ago on 90% highway driving. This tank it's looking like I'll get 37-38 mpg doing 75-80% city driving
 

psrumors

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Joined
Feb 14, 2013
Location
Cartersville, GA
TDI
MK4, MK6
We took a trip yesterday where I would normally get 48ish mpg and I only got 42. Intake air temp was between 27 degrees and 36 degrees the whole trip. Seems anything below 40 degrees and my car gets "poor" mileage.

I've thought about getting a cold front for the car but really don't need one very often here in GA.
 

Diesl

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Dec 3, 2012
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Chicago
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'78 Golf Diesel (long gone); 2012 Jetta Sportwagen TDI w/ DSG
I have been keeping track of my diesel mileage for the last two years, and see about 5-7% variation winter to summer; see the link in my signature. I do 40 mile commutes with ~1/3 city 2/3 highway.
 
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Wankel7

Veteran Member
Joined
Dec 25, 2012
Location
Indiana
TDI
2003 Jetta Wagon
2013 6speed manual Jetta
for the past month I've been averaging only ~37mpg (commute is mixed driving, maybe 60-70% highway)

Prior to that I would average around 42-43mpg. Best tank I've ever had was around 46mpg (was in September).

Is that a normal hit to expect? Sometimes as much as I love the TDIs (I had a 2002 before this one), I think maybe a gasser econobox might have been a better value :(
Block off the radiator and do a Frostheater and you might get most of it back.
 

Cogen Man

Veteran Member
Joined
Jun 4, 2011
Location
Kingston, Ontario, Canada
TDI
2011 Golf TDI DSG.
ALH's do lose FE in winter, but the newer cars lose more. They expend more fuel in warm up to heat up the emissions equipment quickly, and have more electrical losses (heated seats, electric cabin heater).

I find winter fronts on both cars help. I've been getting 46 pretty consistently this winter in my ALH driving mostly highway. My Golf on short trips in the winter will get around 40, whereas I see 43 or so in similar driving in summer.
Best mod I have done is a winter grill block for my 2011 Golf TDI from IDparts.com. Big reduction in engine warm up time on a stone cold engine. That equates to better FE overall. The big hits to FE for me are winter fuel, winter tires, cold temperatures(the grill block helps with that). I try not to use the heated seats but if you got them why not use them. Toasty buns are a good thing.
 

ScottySK

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Joined
Dec 18, 2012
Location
Beaumont, AB (CA)
TDI
03 Jetta GLS
I block off the grille for the IC as well, IATs are about -15 when it's -30 ambient. I also block off the cold air inlet and open up the intake tract to the warmer engine compartment. Still pulling 700 mile tanks (5-5.2L/100km) with my 16km commute in -30C or worse weather.
 

Dannyboy

Veteran Member
Joined
May 25, 2013
Location
Mb
TDI
2014
Interesting...do you block it at the IC or at the bumper inlet?
What kind of temps are you seeing?
Same as Scotty, block the grill off. the temps depend on temps outside and gradient . just crusing on the highway -15c sees around -5c to 0c average on intake temp but it does vary. Never really see anything above 14c inlet until outside temp is in single + figures or going up a long hill. but nothing i would worry about in the slightest.

I know it's a gasser but i used to drive my 1.8t during winter the fuel economy would drop 20-25% because of the massive IC and 102 octane fuel it ran on. Boarded up 50% of ic/rad and ran it on normal unleaded. About 7-9% of the FE returned.
 

tedd

Member
Joined
Oct 8, 2014
Location
uk
TDI
polo 1.4tdi-pd (AMF engine, 2001 SE spec)
Same as Scotty, block the grill off. the temps depend on temps outside and gradient . just crusing on the highway -15c sees around -5c to 0c average on intake temp but it does vary. Never really see anything above 14c inlet until outside temp is in single + figures or going up a long hill. but nothing i would worry about in the slightest.

I know it's a gasser but i used to drive my 1.8t during winter the fuel economy would drop 20-25% because of the massive IC and 102 octane fuel it ran on. Boarded up 50% of ic/rad and ran it on normal unleaded. About 7-9% of the FE returned.
can you post pics of the grill block in action.
thanks.
 

Dannyboy

Veteran Member
Joined
May 25, 2013
Location
Mb
TDI
2014
can you post pics of the grill block in action.
than it.
Im in Germany at the moment and the cars in Canada so i cant show you it but im sure one of the guys will chime in with a picture.i just used some pipe insulation (youll get it at B&Q) and cut to size. I got the one with sticky strip so it stays attached to the grill
 

Steve Addy

Top Post Dawg
Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
I need to do something, going to get some coroplast and make a grille cover, upper and lower. My normal mpg is 50+ but the nasty winter blend and weather conditions takes it down into the low 40's.

Steve
 

SkeeterMark

Veteran Member
Joined
Jan 8, 2013
Location
North Branch, MN
TDI
2013 Jetta TDI 6M
ALH's do lose FE in winter, but the newer cars lose more. They expend more fuel in warm up to heat up the emissions equipment quickly, and have more electrical losses (heated seats, electric cabin heater).

I find winter fronts on both cars help. I've been getting 46 pretty consistently this winter in my ALH driving mostly highway. My Golf on short trips in the winter will get around 40, whereas I see 43 or so in similar driving in summer.
Are you sure about this? Mine seems to heat up (actual coolant temp) WAY faster my friends ALH. My theory was recycling more exhaust kept more of the heat in and around the engine where the older models just send it on out the tailpipe.

I have been keeping track of my diesel mileage for the last two years, and see about 5-7% variation winter to summer; see the link in my signature. I do 40 mile commutes with ~1/3 city 2/3 highway.
I concur with Diesl, and keep similar stats.

Winter fronts help, but I still think the OP is in the ballpark for "normal" winter vs. summer mpg.

And don't think for a minute a gasser does not suffer as well. Some even worse because more people are inclined to let them "warm up" for long periods of time. More so than us diesel drivers, since we know we have to get going to produce any significant temp increase.
 

IndigoBlueWagon

TDIClub Enthusiast, Principal IDParts, Vendor , w/
Joined
Aug 16, 2004
Location
South of Boston
TDI
'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
They do heat up faster, but it takes fuel to do it. And the electrical losses are greater, so FE suffers more. ALHs are cold longer, but don't expend as much fuel trying to get up to temperature. At least that's my experience.
 

petee_c

Veteran Member
Joined
Jun 2, 2014
Location
Heidelberg, Ontario, Canada
TDI
15 Golf TDI, was 06 Jetta TDI, 15 q7 tdi, was 11 Q7 TDI
I've seen a big drop in Fuel Economy in the past couple months. This is my 1st winter with a 2006 Jetta TDI 5speed.

In September, I was averaging about 5.5L/100km, then in November I put winter tires on, and got probably about 5.7L/100km. It's been pretty cold the last few couple weeks in January. My 2nd last tank, I calculated about 6.4L/100km, and my last tank was over 7.0L/100km ( 28.xL/410km) I had a little more city driving than normal (trips under 20km) on the weekend as we were out and about a bit. The weekend was seasonably cold, but the last 2 mornings it's been near 0F on the morning commute.

Last night, I bought 12' of the black foam insulation for 1/2" copper pipe from Home Depot. Used it on the upper and lower grill. The needle on the temperature gauge got up near 90c in about 10km (6miles) of country driving. The car was in the garage and registered -8C on the dash, but the air temperature was -20C to -24C at work. I had a 80km (50mile) commute this morning.

Hopefully I'll be in the low 6L/100km range my next fill. Likely as I've got about 500km of almost all highway driving over the next 48hrs.
 

VeeDubTDI

Wanderluster, Traveler, TDIClub Enthusiast
Joined
Jul 2, 2000
Location
Springfield, VA
TDI
‘18 Tesla Model 3D+, ‘14 Cadillac ELR, ‘13 Fiat 500e
They do heat up faster, but it takes fuel to do it. And the electrical losses are greater, so FE suffers more. ALHs are cold longer, but don't expend as much fuel trying to get up to temperature. At least that's my experience.
Right on the money. Commonrails end up wasting a lot of fuel warming themselves up, unlike the ALH which just freezes your ass off in the winter.
 
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