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I'm a new Touareg owner -- 2012 TDI Executive with 77K miles. I just finished a 200 mile round trip towing a load, which is my Can Am Maverick Trail 1000 side by side on a single axle 14 ft aluminum trailer. I'm estimating the total weight to be 2800 lb with about 300 lb tongue weight. The trip is maybe 40% flat and the rest hills and a total of 30 stop signs/lights. Speeds ranged from 30 to 70 mph. According to the vehicle computer, I averaged about 15 mpg. On the freeway flat straights, the real time computer showed 14.5 mpg at 65 mph. I've read many posts from other TDI owners claiming close to 20 mpg on the highway towing more than 5000 lbs. Something is amiss here. Prior to the trip I ran the "original unknown type and age" fuel down and put in 22 gallons of Marathon diesel with 16 ounces of Power Service Diesel Kleen with Cetane Boost per my local VW service manager's suggestion, and I was "getting on it" sometimes going through the gears manually to get over 3000 rpm while upshifting. Something I did notice is that in 8th gear and 65 mph, when I'm going up a hill, I can sense a very slight surging -- almost feels like a gas engine that's got an ignition issue or bad gas. That's the only time I notice this, but it can be repeated consistently. This is my first diesel vehicle so I'm a complete newbie when it comes to how they're supposed to run. Any suggestions would be appreciated.
 

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Have you changed your fuel filter yet?
Yes -- the VW dealer I purchased it from performed several maintenance items to prepare it for sale, including replacing the fuel filter, engine oil & filter, engine air filter, cabin dust/pollen filter, main battery replaced, rotate tires (almost new), front & rear wiper blades, topped off Adblue.
 

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2014 Audi Q7 TDI
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The best fuel economy I've ever had towing was coming down out of the mountains w/a tailwind.. got almost 18mpg with my ~6klb trailer staying under 65mph.

Its very subjective to how you drive, where you drive, and the aerodynamic qualities of what your towing.. 14-15mpg is pretty average for me with my big trailer, terrible headwind and I'll be down to 12mpg at interstate speeds, and its not much different the FE I had with a lil Cricket camper I rented and pulled through the mountains.. 30 stops seems like quite a bit for just a 200 mile trip, at interstate speeds I stop once every 300-400 miles to refuel and thats it.

20mpg pulling anything more than a lil 1500lb trailer small enough to draft behind you seems quite ambitious IMO.. take comfort knowing if you pulled it with a gasser you'd be getting single digit FE with this tow.
 

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Discussion Starter #5
The trip was a combination of going through towns (Grand Haven MI) with stop lights and a number of stop signs in rural areas. If you're getting 14-15 with that 6K lb trailer and I'm getting the same with 2800 lb (probably less in reality), I'm definitely way below you on mpg. The previous (original) owner was based in Danbury CT, so I'm guessing that he had quite a bit of stop and go driving and congestion that typifies daily life near NYC. So I'm hoping that some regular highway driving along with the Diesel Service additive will help to clean out the injectors and other parts of the system. I didn't mention it in my original post, but after as little as 10 miles of 55+ mph driving, there is a light coating of "yellow dust" on the back window and door (when I wipe it off with a damp white cloth it shows yellow). Someone told me that it's typical, but I can't find anything online about it. I can't believe that it's normal, so maybe it's a symptom of what's going on with the high fuel usage.
 

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the weight matters very little.. once you got it moving.. the cricket camper I rented weighed less than yours and I found the FE between a 2000lb camper and a 6000lb camper on highways to be very minimal, like 15-16mpg vs 14-15mpg between the two, all drag at that point is from wind resistance and we're cruising right at peak torque.. now if you have to sit in traffic, tow through the city, then all that goes out the window and the heavier load will drop down to single digits mpg just because getting it going from a stop destroys FE... I run no additives but some BG245 through every fuel filter.

Yellow dust? never have any kinda residue on back of mine.. no idea wtf that is, only time I see anything like that is from pine pollen in like June.. but it covers absolutely everything with it.

Fuel Economy is all over the place when towing, how fast are you getting up to speed, how often you have to use brakes, what kind of winds your looking at, what kind of inclines your looking at.. have to use long term averages and even then I see several mpg swings in either direction with very little differences in load.. Ive been stuck in traffic going up to the eisenhower tunnel getting 6-8mpg on the MFD.
 

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That's pretty amazing that doubling the trailer weight doesn't make much mpg difference -- I suppose that's a key advantage to diesel engine physics vs gasoline. Since I can't find anything online about the yellow exhaust dust, I'm wondering if the previous owner might have used off-highway diesel fuel by mistake (hope not intentionally)? Apparently that stuff is extremely high in sulfur content compared to the road-approved stuff. The car's now at the shop getting an exterior detail, so when I get it back, I'll check the back window after getting home (9 miles mostly 60 mph) to see if it still has the yellow dust after running 200+ miles towing on fresh fuel and the cetane additive. If it does, I'll contact the VW dealer and see if they can try to diagnose the cause. I'm guessing it's related to the slight surging I felt and heard while trying to maintain 65 mph up a long hill while towing in 8th gear.
 

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2015 (2016 MY) Touareg SE 3.0 V6 TDi 262PS
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Towing a 1500kg caravan at the 60mph UK towing speed limit, I average 22 mpg Imperial but headwind/tailwind can give silly figures above and below that.
 

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So while not "towing" we recently got home from from a ~3000 mile round trip. We had 2 kayaks, 2 paddle boards, and fishing poles on the roof. Usually I get between 28 and 32 mpg commuting. The drive down we got ~20 mpg with everything on the roof. On the way home the first several hours, about 1/3 of the trip, there was a strong headwind and it knocked us down to about 16 mpg. Moral of the story is, aerodynamics have a HUGE impact on the fuel mileage of our Touaregs.
235992
 

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Wow, that's quite a roof load and a trip for the ages! It's interesting how much aerodynamics play into the MPG equation. I suppose that's why so many cars and SUVs look the same now -- there's probably a magic design for each that works the best in a wind tunnel.
 

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Your 2012 fuel economy sounds perfectly normal for a diesel Touareg. If you were driving through Ohio East-West you would expect 20 mpg. But you mentions climbs, and that alone will bite your fuel economy in a big way.

Trailer and load aerodynamics are huge. Stop and go is huge (you just won't get and fuel economy back going downhill). Climbing is huge. Trailer weight matters a LOT when stop and go driving, and climbing, but not so much once up to speed on the flats, you're really fighting the wind at that point, and faster is harder and less fuel efficient.

I would get actual 11 mpg towing an R-Pod travel trailer (3000 pounds about) with a 2003 V6 4Runner 440 miles round trip. But after buying the Touareg TDI, I still only achieved 15 mpg on the exact same route same speeds same time of year....... Not a huge difference in mpg, but effectively 36% better fuel economy.

But my new small toy hauler is about 5500 pounds loaded, and I get 14 mpg - the EXACT same 440 mile round trip. When I used to HAVE to stop an fill up (19-20 gallons) with the 4runner (21 gallon tank), I can now get to my campsite with the Touareg and top off (16 gallons of 26.4 gallon tank) before returning home. There are some benefits of having a diesel. And if I ever have to tow at over 50000 feet, the power drop off is far less in the turbo diesel.
 

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Aerodynamics makes such a huge difference, my Golf TDI I had an aerodynamic little trailer that slipstreamed behind me perfectly.. with 1500lbs in tow it got ~36mpg avg @ 75mph, with a Roof Rocket would get worse MPG than that empty.. put 40k miles on that setup and it was sooo cheap to slam down miles.

@Megaboss268 might be better suited by putting all that gear on a small lil trailer that fits within your profile.. would see less impact on the fuel bill and if thats a way you ride frequently it could pay for the trailer and be in the green pretty quick if you keep it simple like a modified jetski trailer.
 

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Discussion Starter #13
Hey I really appreciate the feedback and sharing your own MPG experiences with your TDI machines. Just today I drove it about 20 miles, and during that time, I observed about 35 mpg on a straight and level stretch at 58 mph, which is something I hadn't seen before. I'm hoping it's the fresh fuel and Power Service additive working its magic. Once I get down to 1/4 tank and fill with fuel, I'll reset the trip odometer and drive it "normally" without a trailer. Once I'm below half a tank I'll refill again, document the fuel used and mileage, calculate the mpg and post the results on this thread. Note that right now here in MI the diesel is "winter blend", and I'm told that this formulation can negatively affect mpg around 5% compared to the "warm climate blend" that is available once the weather warms up.
 

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Try resetting your gearbox.

Turn the ignition on but do NOT start the car.

Press the accelerator pedal firmly to the floor and hold it there for a full 10 seconds.

Release the pedal and turn the ignition off.

The box should now learn how you drive the car.

Everyone should do this if the car is new to them or their style of driving has changed or any other significant changes take place such as after towing long distances.

The only real way to judge MPG is by filling the tank, putting on the miles and then refilling the tank and doing the math!
 

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Original poster -there are a million things to take into consideration here
1- the shape of the trailer (and its size) - depending how fast you're doing on the highway it can create huge amounts of drag
2- you said that, on presumably the same tank of fuel, you were thrashing the car.. obviously this is going to take a hit on economy
3- if you JUST started running diesel kleen it can take a full tank or two to clean the system out
4- its winter time.. all cars but especially diesels take a huge hit in economy.. diesels take FOREVER to warm up, and winter fuel blend is far less efficient than summer fuel blend
5- 30 stop and goes?!?! thats a ton!! your trip sounds more like a city commute than anything, not to mention you said around ~60% hills
6- you transmission is still relearning how you drive - this will have a huge affect on economy and shifting characteristics
7- if you drive like a jackass, you're going to get poor mileage. If you floor it everywhere.. well, this is a no brainer
8- DONT TRUST THE DISPLAY. Just run a full tank and hand-calc it. My display is NEVER accurate tank-to-tank, but is literally spot on to the 20th of a percent

When I pull my ~5k boat to the marina, its uphill the whole way there and mostly downhill the whole way back and with a car full of people and a loaded boat (speeds not going over 50mph) I usually end up averaging around 20mpg
 

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I towed a ~2900 lb 16' Scamp from Florida to the west coast and points between.
We averaged 20 MPG for the trip with our 2012 TDI Exec.
I refilled the DEF in Albuquerque adding ~ 4 gal.
We towed from sea level to close to 10,000 feet.
Traveled at the speed limit for trailers where ever we traveled (if safe, of course).
The Touareg has proven to be the very best tow vehicle we have used bar none.
I just left the transmission in auto and only shifted when descending steep grades to save the brakes.
The 3.0 TDI Diesel is a great engine and never seemed the least bit strained.
 

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Let your automatic transmission do it's job and the shifting for you, instead of running the engine up to 3000 rpm. Peak torque is full in at 1750 rpms, less with 2011-2012 models, closer to full in boost at 1550 rpm.

If your engine is running up to 3000 rpm, try manually shifting it at 2300 and keeping the rpms at 1900 to 2000 just after the manual shift. That will help your MPG. So will lowering your towing speed. You make no time between driving 55 and 65 or 70 mph if towing less than a an hour or so, you lose it all in city traffic stop lights, making time while traveling. The only time to drive 70 instead of 55 or 60 is if you're doing 300-400 or more miles in a day, otherwise, the wear and tear, wind resistance and work load just tear up your drive train while trailering. You should never expect a little 3.0 liter LIGHT DUTY sedan diesel to do heavy work, maybe only infrequently. When you need to do work, with a diesel engine, you need displacement, cubic inches not cubic centimeters.
 

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^^True regarding shifting. When the car detects a trailer it goes to completely different transmission tow mapping. Never ONCE have I wished my Touareg was in a different gear or a 'better' gear, and I've got a LOT of experience towing really big, heavy stuff with a wide variety of tow vehicles (some with excellent tranny programming, some with abysmal). Just put it in drive and let the car do what some of the best engineers on the planet have decided it should do under load.
 

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I'm in manual mode coming down mountain passes for maximum engine braking, afterwords once I'm back down to flat ground I need to keep it in Manual mode a bit or else it will have adapted to my braking and then it wants to shift all wrong.. but it dont take much for it to get back to sane values.. every other time it shifts great
 
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