Options for Diesel Cars

March 17, 2005 8:25 AM

I love my car, but am becoming increasingly concerned about gas mileage and environmental responsibility. It isn't a guzzler, but I know I could do better. What are your experiences with diesel cars?

Currently I drive a VW Passat Wagon with all-wheel drive. It's been a pleasure to own, and I can't think of a single complaint. In fact, I really would be sad to part with it, since it's been so good in snowy weather with the all-wheel drive, and the storage space is great.

And yet... I get an average of 25MPG, and I sometimes take long trips where this really adds up. I've been looking more into switching to something that gets better mileage. Diesel seems to be the best option (perhaps with a conversion kit for veggie oil, even).

If there was a diesel Passat Wagon with all-wheel drive, I'd switch today, but as far as I can tell, this doesn't exist.

Are there any all-wheel drive diesel cars out there? What's your experience with diesel cars in general? Does anyone have first-hand experience with bio-diesel or vegetable oil conversion kits? I'm partial to VW because I've had such a great experience, but I'm open to new options. I have no prior diesel experience myself.

posted by odinsdream to travel & transportation (11 answers total)

I looked at the VW diesels when I was buying a car a couple of years ago. The gas mileage is fab, but it turns out that they are not so kind in terms of pollutants released. I ended up with a regular old Honda Civic, which gets about 35 mpg on trips and is a Very Low Emissions Vehicle.

There is an EPA/DOE website that has info arranged by model and size etc. It tracks both fuel economy and emissions.
posted by OmieWise at 8:42 AM on March 17, 2005

I think there IS a diesel Passat Wagon. From the page OmieWise linked to:

http://www.fueleconomy.gov/feg/best/bestworstNF.shtml

Look at the Most Efficient Midsize Station Wagons.

This has got my interest peaked as well since I'm looking at getting a new car sometime soon and am concerned with fuel efficiency and such. Hopefully some more knowledgeable people will pipe in the goods and bads of diesel like you asked for.
posted by gus at 9:28 AM on March 17, 2005

I love my jetta tdi but I know the diesel options are limited in the US (even GM makes diesels for europe). I run biodiesel (B2 and B100) whenever I can and it works just as well. If you have the means, the VW Toureg is available in an 4WD V10 diesel that ,by all accounts, it kicks serious tail. I also hear that Jeep is releasing their Liberty in diesel. It should be 4WD and comparable space to your passat wagon (though taller and obviously more SUVish)

Per the emmissions of diesel - this generally gets better when all commercial diesel goes low-sulfer next year. With this, the engine becomes more sootless, even without modification. With mods, engines will be very clean.
posted by jmgorman at 9:37 AM on March 17, 2005

Are you sure you can't live without AWD? It's a drain on gas mileage, and it looks like you live in a warm-weather state.
What jmgorman said about diesel emissions.
posted by willpie at 9:49 AM on March 17, 2005

In fact AWD is rarely the snow-saviour it professes to be. While you may have an extra two wheels worth of traction to push through the bank left by the plow, you're still only really using two tires to brake.

As for diesel, the Volkswagen TDI is a beautiful piece of engineering, and you'll love the money you save at the pump. I wouldn't say they pollute any less though. Take a look at the EPA website linked above. Diesel engines tend to pollute less on the 'global' scale (CO2), and more on the 'local' scale (Sulfur dioxide, particulate mater and carcinogous hydrocarbons). I am particularly concerned with the particulate matter emissions as recent studies have shown they can lead to germline-mutations.

Biodiesel eliminates these pollution concerns, but gells at relatively high temperatures, so isn't much use in my part of the world
posted by Popular Ethics at 10:10 AM on March 17, 2005

Try looking around at TDI Club in their Forums for info on VW TDI Diesels. Its a great owner community with lots of existing threads talking about your concerns.
posted by jduckles at 10:19 AM on March 17, 2005

What interests me most about diesel is the much-increased mileage as well as the ability to easily run on biodiesel with very few, if any, engine modifications. This seems like such a great feature reading about it, but of course I have no actual experience with it.

As for the all-wheel drive, I can't say scientifically that it's helped my snow driving (which I do a fair amount of despite my zipcode, as I travel north frequently), but I was under the distinct impression that it had. The Toureg is definitely interesting.

I had not heard that diesel may actually pollute more than gas. Most local places do use low-sulfur diesel now, should that help?
posted by odinsdream at 10:28 AM on March 17, 2005

I believe that the US is going to switch to low-sulfur diesel in the near future. Particulates largely arise from hard acceleration (diesels don't have a throttle to regulate the air flow, they regulate power by fuel flow, romp the pedal at low rmps and the ratio of fuel to air becomes too rich. The hydrogens burn off first, leaving the carbon). Less of a problem in light weight cars (as opposed to city busses). I love my '82 Suburban diesel, 4x4 for offroad, pulls a heavy trailer, seats 9 and in spite of weighing 8000 lbs. gets a measured 23-25 in mixed driving (I know, nothing like new car, but I only paid $1000 for it). If I were putting lots of miles on it, I would burn biodiesel, but biodiesel dissolves deposits in the fuel system left there by regular diesel. Not a problem for a new car, but it would probably require many fuel filter changes in an old (and abused) vehicle like mine.
posted by 445supermag at 10:44 AM on March 17, 2005

One thing about running on biodiesel that you should check out (if thats a motivator for you) is if its available in your area. In my particular area I haven't found a retailer closer than 30 miles from me so I wind up using dino-diesel mostly.

Bio is claimed to be better on your engine due to its natural lubricating qualities. On TDI Club there are whole threads talking about people's experiences with ESP making their winter driving that much safer (not 4WD but suposedly helpful in winter driving). I personally didn't get ESP on my TDI, but I grew up driving in snow and like to be in-tune with the feedback my car is giving me.

Also, I should mention that diesel prices are running a bit higher than gas at the moment. You might want to factor that into your analysis if you purely economicly focused and not entirely bio-friendly focused.
posted by jduckles at 10:46 AM on March 17, 2005

Couple of things I noticed poking around a bit: Bio seems to result in about a 10% mileage drop compared to "regular" diesel. That still may be better than a traditional gas vehicle, but coupled with its higher price, I'd want to run a pretty thorough C/B analysis. I'd probably be willing to pay a higher price (and less mileage) for the better emissions/lack of petroleum usage.

Saw a lot of Passat Wagon TDIs, but it appears they're all the older (pre-1998 I believe) iteration. I think the current Jetta wagon comes as a TDI; of course you lose the 4-motion and the extra space.

Might some of the new hybrids coming on the market make sense? The new Toyota Highlander and Ford Escape both look intriguing, though admittedly more SUV-ish than I'd want.
posted by jalexei at 11:12 AM on March 17, 2005

Why diesels are not your friend. From a previous discussion.
posted by NortonDC at 11:56 AM on March 17, 2005