Slightly OT: Petrol or Diesel?

Which is preferable these days, for economy: petrol or diesel?

My friend reckons diesel still, but I wonder about that, since the price of diesel is now higher than petrol, and since dealers are still charging a premium on the price of diesel vehicles.

[The fact that car dealers charge a premium for diesel vehicles is not necessarily a guide to their being superior -- rather, that customers are willing to pay more.]

Ta John

Reply to
Another John
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How long's a piece of string?

What _real world_ MPG do each get? What's the purchase/depreciation difference? What's the maintenance score on each? Not just routine, but with an adjustment factor for likely other failures. F'rinstance, DMFs/DPFs can get very expensive, very quickly. As can mis-fuelling a common-rail diesel.

Work each of those out to pence-per-mile, then figure in the annual mileage, and you'll have an answer.

Reply to
Adrian

It depends on what type of engine you have.

Reply to
Frank Erskine

The answer will vary from case to case. You can calculate the difference in cost of fuel per mile from the manufacturer's figures fairly easily. You then need to modify that by a factor that allows for the difference between what mpg you get in practice, as compared to the manufacturer's figures, on whatever car you drive now and hope it is much the same. Then you need to divide the extra cost of the vehicle by the number of miles you expect to do before changing the car.

Looking at my next car, I can justify the extra £1,200 for diesel, but not the extra £3,000 for a hybrid, on fuel savings.

It is generally a reflection of the difference in the cost of building the two types of engine. Diesel engines need to be a lot more sturdy than petrol.

Colin Bignell

Reply to
Nightjar

New or second-hand? What mileage do you do?

FWIW I replaced my main car, previously petrol, with one of the last non common rail diesels. Next time I will probably go back to petrol, betting that the risk of a large bill on a common rail for ECU, injectors, etc. offsets the reduced economy.

At one time I reckoned that ignition faults on petrol cars gave diesel another "edge" but I don't think this is true any more.

Reply to
newshound

I think over here we see special rates of congestion charges being taken away for Diesels etc, due one assumes to the particulate issue.

Brian

Reply to
Brian Gaff

Diesels (in general) cost more to make. The engines have to be made of stronger components.

Open road fuel consumption between both has come much closer these days - but diesel still wins if you do lots of town running/short journeys. Whether this will save actual money depends on circumstances. Don't forget the depreciation difference as well as initial cost too when doing any calculations.

Reply to
Dave Plowman (News)

Modern Euro V diesels with DPFs don't get chance to regenerate unless you have a long/fast journey when it needs one ...

Reply to
Andy Burns

For new cars, p'raps.

But I think he meant for used cars - which is entirely down to market factors, supply and demand. The truth is that Joe Average firmly believes that a diesel is inevitably going to cost buttons to run whilst a petrol will rape your wallet daily. With more and more personal DPF experiences, that's already starting to change - and will only continue to do so.

I'd suggest that buying a nearish-new used diesel now would be a great way to learn about steep depreciation.

Reply to
Adrian

Really? I thought that Diesel engines took longer to warm up and achieve maximum effeciency.

Do equivalent cars with petrol engines depreciate faster or slower than cars with diesel engines?

Reply to
Mark

Diesel is still, on average, more economical at the pump. But as you identified whole life costs are more difficult to factor, especially since you must now add VED into your calculations.

I still think that the broad advice that a diesel is better if you do high annual mileage and a petrol if you do occasional trips holds. ie petrol for pensioners, diesel for reps.

FWIW I have two cars fuelled on LPG and that suits me fine.

Reply to
Steve Firth

Yep this is exactly why I bought a diesel 20 years ago. Ran it for 13 years until I wrote it off in a prang.

But this reason is no longer a consideration and I wouldn't buy one now

tim

Reply to
tim.....

They do take longer to warm up, but don't need a rich mixture while doing so - like a petrol car. A petrol car's fuel consumption is positively horrendous during this period.

I dunno. And I'd guess it depends on model too.

Reply to
Dave Plowman (News)

Strangely, I used a diesel for a few weeks last year. Belonged to a deceased pal. Who was very definitely a low use pensioner, being disabled too. It was a Susiki Splash. Went very well too, in town, despite having the AC on all the time. I only used it in town with many short journeys - arranging things after he died. It averaged 45mpg. I was impressed. As regards overall costs - purchase price and depreciation etc, I've no idea. I constantly told him he should have a nice secondhand Rools given his tiny mileage. And him buying a brand new car every year. Still, I suppose he could afford it living in a tiny council flat...

Reply to
Dave Plowman (News)

On 24/07/2013 10:10, Adrian wrote: ...

The best way to learn that is to buy new and watch the value plummet as you drive out of the dealership.

Colin Bignell

Reply to
Nightjar

Today's diesels are about 40% longer lived and 40% more fuel efficient, much of which is negated by the fact that diesel is now more expensive than petrol. They are also less expensive to maintain. No plugs for a start.

So Id tip the balance towards a diesel frankly, but there isn't a huge amount in it really.

Reply to
The Natural Philosopher

I cant say I have had any problems with any diesels I have had. One limped home witha split turbo hose. It aslo had a fuel pump die (60,000 miles). I have had more problems with petrol always.

But really. apart from fuel pump or batteryfailures its rare for any modern engine to let you down.

Reply to
The Natural Philosopher

I'm a pensioner and diesel works better for me.

Colin Bignell

Reply to
Nightjar

In message , "Dave Plowman (News)" writes

in reply to

I'll quote again my experience with short mileages moving the elderly (0.5 mile, long wait, 0.25 mile, long wait, 0.1 mile, very long wait,

0.5 mile, shortish wait, 0.5 mile home). Repeated frequently per day. Omega 2.2 petrol auto 7.0 to 9.8 mpg auto choke being the killer Disco 2.5 diesel auto approx 15 mpg Octavia 1.9 diesel manual 30 to 35 mpg

On long runs we peaked at 40 mpg in the Omega, 30 in the Disco and 70 in the Octavia.

We sold the Omega because of maintenance costs at 100k miles ( to be fair earlier Omegas were just traded in at 200k) The Disco does mainly other hard miles (towing etc) and has had few problems except rust. The Octavia has had no real problems although SWMBO hates it because of the hard suspension and my gear changes.

Npne of these have DPF's. If I were buying now I would look for a pre-dpf slushmatic type auto diesel vehicle. Son had an old Merc that I thought was great.

Reply to
Bill

On 24/07/2013 12:37, Dave Plowman (News) wrote: ...

For very small mileages, the fixed costs of owning a car probably make it more economic to use minicabs instead.

Colin Bignell

Reply to
Nightjar

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