car gas diesel used

June 6, 2007 9:13 AM

Diesel vs. Gas used car. Help me decide.

We want to get a used car. I'm seeing some decent, not too old gas engine cars for 1000-2000 euros and some decent, not too old diesel engine cars for 4000-6000 euros.

I drive alot with work and find that when I rent a car, the cost of gas is significantly less with a diesel engine. But how can I better calculate the actual initial cost vs. ongoing cost saving? Does anyone have any experience or know any rules of thumb?

posted by BigBrownBear to travel & transportation (16 comments total)

I drove an old diesel for many years (and oh, I still miss that car). Cost differences will also be affected by maintenance issues - there are some things you just don't have to worry about with diesel engines (spark plugs, etc). So factor that in, as well - someone can probably give you a far better idea of the maintenance differences than I can.
posted by dilettante at 9:24 AM on June 6, 2007

Here's a list of pros and cons I've found by searching for "diesel car vs. gas car" - diesel engines will last twice as long, and get better gas mileage, so that has to be factored in as well.
posted by muddgirl at 9:27 AM on June 6, 2007

Also, it's not strictly true that diesel is always cheaper than gasoline; here's an article about a surge in diesel prices in 2005.
posted by muddgirl at 9:31 AM on June 6, 2007

two points i should have mentioned (1) i live in continental europe and (2) i've done some google searches that didnt help much. i'm looking for some more experiential or financial arguments on one of the other.
posted by BigBrownBear at 9:35 AM on June 6, 2007

I drove a diesel volkswagen for a number of years. Somethings to keep in mind:
1. Cold weather. Diesels start harder. Do you have access to a plug-in near your parking place? Does the car have a block heater?
2. Slower. Diesels have slower acceleration. Are you prepared to sacrifice speed for frugality?
3. Smell. I like the smell of diesel. Can you live with it long term?
4. Mechanic. Do you have access to a mechanic who knows about diesels?

As far as costs, hows this:
(initial cost) + ((avg # of km/yr)/ avg kpl) x cost of liter of fuel. That gives you the basic costs for the first year.
posted by cosmicbandito at 9:46 AM on June 6, 2007 [2 favorites]

in response to the post above
05 VW Golf TDI

1) no experience here but no issues during the winter in MD
2) my VW Golf accelerates like a bat out of hell - lots of torque...zero issues with merging into heavy traffic (70, 270, DC beltway when it's not at a stand still that is)
3) no issues here, just avoid getting it on your hands as it does stay a bit longer than gas but it's not like you'd be pouring it all over yourself either
4) so far no issues (of course still under warranty) with engine
posted by evilelvis at 10:15 AM on June 6, 2007

Several years ago I test drove a couple of Jettas, one with the mid-range gas engine (not the turbo, nor the anemic one, I forget what the displacement was) and one with the turbodiesel engine. They performed essentially the same in acceleration when they were both driven like gas cars.

Once I realized how much torque the diesel had and kept the RPMs down, the diesel performed better than the gas.

Since I didn't buy either of them, I can't say much more than that, except that I've been told that old Mercedes turbo diesels were great, except that the turbo didn't kick in until somewhere around 15mph, thus making the initial acceleration slow, despite launching you forward at a rapid pace after that point.

Unless the gas car is exceptionally fuel efficient, or the diesel exceptionally inefficient, the diesel will be cheaper in the long run unless the price of diesel is nearly twice as much as gas. Especially over there in Europe where there are more diesels, and thus greater parts availability should something go wrong.
posted by wierdo at 11:11 AM on June 6, 2007

About the only argument left in petrol's favour is that their engines are big-revving, so if you're the sort of driver who likes to hare along and drop into third for overtaking, you want a petrol.

For almost all other uses, get a turbo diesel, of the common rail type. By far the best are the German models -- VW/Audi group, BMW and Merc. The worst were traditionally Ford -- they're trying to get better but goddamn some of their boxes sound like a skeleton having a wank in a filing cabinet. In-between is Peugeot/Citroen.

A modern diesel engine, with common rail, like the VW Golf TDi is like voodoo: goes like thunder, but returns great mileage, lasts years longer, and is reasonable to service.
posted by bonaldi at 11:39 AM on June 6, 2007

(However, don't get a turbo-less diesel. The Golf one is branded SDi. They are slo-o-ow.)
posted by bonaldi at 11:40 AM on June 6, 2007

With diesel, you at least have the option of creating your own fuel in your back yard. A gas engine is harder to fuel without the whole infrastructure thing.
posted by yesster at 12:45 PM on June 6, 2007

Not to hijack, but I'm curious how an American diesel engine like a Cummins turbo diesel stacks up to a BMW/VW diesel. Obviously the Cummins are used in trucks & not so much cars, but given that difference, are they significantly behind the European diesels, or roughly on par now?
posted by devilsbrigade at 12:50 PM on June 6, 2007

I'm not sure -- I know a Cummins truck was one of the world's fastest, but the diesel market in Europe is ferociously competitive, and most of the advances I've heard of come from Germany. Ford opened a new diesel engine design centre in 2006, but that was in England. Certainly the best diesels I've driven professionally were BMWs and VAGs.
posted by bonaldi at 1:11 PM on June 6, 2007

Former diesel mech here. Seconding bonaldi, don't get anything that is not turbo. Turbo-less is what we used to call a "dirty burner". You'll probably still see some older Mercedes out there that spew dark smoke. They are slow and don't have the same mileage/kilometrage(sp) as a turbo.

If you do get one, make sure to keep the fuel system clean. Diesel is kinda nasty and is much more quick to clog up injectors and pumps. (the only draw back AFAIK)

American vs. Euro/German? I don't wrench anymore, but I still check around sometimes and the engines in USian big-rigs still don't look very different from what you would see in an old Deuce and a half ('40s era army truck). Considering price and tech, I would go with a big Volvo engine. I see them everywhere, and never broken. They're really big in the nautical industry too.
posted by snsranch at 2:22 PM on June 6, 2007

BIODIESEL!
posted by sunshinesky at 3:26 PM on June 6, 2007

I'll chime in. You're in europe, a place much friendlier to diesel than here in the states---you also have more options than we do. Basically, here, we have 2 choices for diesel cars, VW's and Mercedes. Also, the only 07 VW is a v10 Toureg, as VW is retooling their motors for our new low-sulphur emissions requirements. (Stupid, because simply making all diesel B10 would mean lower than actually formulating new diesel...)

Anyway. Diesel basic maintainence is easy: Change the oil regularly. Run some cleaner OR Biodiesel through the tank every 5-10k miles to clean out the gunk. Drive, enjoy.

In reference to what everyone else has said about common issues:
1. Temperature: if you're not in a place that doesn't get -10 degrees sustained (F, not C), you're not going to have any concerns. If you have a garage, you're fine. There is winter diesel to take care of this problem, plus glow plugs, and you're NOT going to get a car w/o glow plugs. VW's actually have a fuel heater w/i the fuel filter, pretty neat.
2. Smell: the smell is the higher sulfur content diesel---which you have less of in europe. Depending on where you are, you might actually have a bio requirement. (France, for example.)
3. Noise--I love diesel clatter, but it's mostly absent from modern diesels.
4. Acceleration: lots has changed in diesels in the last 15 years. A new-ish VW diesel has 155 ft/lbs of torque at like 2000 rpm's, but only 90HP. A non-diesel jetta has like 120 hp, but only 80ft/lbs of torque. Even "quicker" cars that rev higher don't usually have that much torque-to-weight-ratio. You won't be dissatisfied---and, you can still drop a gear to pass if you need to. However, I often accelerate through 80 mph, up a hill in 5th gear in an american 5 speed diesel jetta.
5. MPG---all things equal, diesels usually get 20-30% better mileage than their gasoline counterparts. A big part if it is that they are significantly more efficient in their combustion. (Jettas will actually have a hard time heating the cabin while stopped in traffic in cold weather)

Just my (too long) 2 cents. I wish America wasn't under the thumb of big-oil, and we could actually have a diesel revolution here. The sticker on my jetta says:
"55 mpg and carbon neutral, can your Prius of crap say that?"
posted by TomMelee at 7:01 PM on June 6, 2007

Oh---for the record. We have a refinery here (small scale) making ~100 gallons a week of bio. We're in the process of building our reactor to move to 1k gals a week from waste oil--so I guess my viewpoint is a little jaded.
posted by TomMelee at 7:02 PM on June 6, 2007