Which is cheaper to run - petrol or diesel?

lordmountararat

Ibrahim5 said:

Have you seen the depreciation on EVs? Fuel might be cheap but the depreciation is off the scale!

The trick is to buy one used with low mileage. I bought a two year old EV last year with fewer than 2000 miles, state of battery still at 100%, for less than half the new price.

Mildly_Miffed

WIAWSNB said:

I also hate the actual 'filling-up' process, and I'm used to near-forgetting how to do it with my current diesel :-)

That's nothing to do with the fuel, or even the economy. It's about the tank size.

I've had petrol cars with 500+ mile ranges and several petrol cars with 150-200 mile ranges, even one with sub 100 mile. Smallest car tank I've had has been sub 20 litres, largest has been 90ish.

B0bbyEwing

Well if you take the old diesel I had & compare it to the old petrol I had then diesel was much cheaper to run. Diesel per litre would've had to have been waaaaaaaaaaaaaaaaaaaaaaaaay higher per litre for petrol to have worked out cheaper.

However take the most recent diesel I've had & compare it to my wife's petrol and the petrol is actually cheaper to run. And to touch on...

"I much prefer a diesel - torque, economics, reliability"

The wife's petrol car as well as the last petrol car I had would absolutely hammer the 3 diesel cars I've had in terms of reliability.

So hope that answer is clear for you

motorguy

WIAWSNB said:

Or, more precisely, by how much? Given, say, an 8k annual mileage.

I know diesel is significantly more economical, but also costs more at t'pump. Diesel engine services are dead simple and cheap - how much more will a petrol service be? 

(Not bothered about PDF and all that malarkey.)

I much prefer a diesel - torque, economics, reliability - but should really be open to petrol alternatives to keep my options as wide as possible. Eg, Mazda CX5 - 2 litre nat-asp petrol vs 2.2 diesel.

Thanks for thoughts and insights

Diesel engines used to be dead simple and cheap.

This past 20 years or so, they've crippled them with DPFs, DMFs, EGR valves and capacities have got smaller using high pressure turbos.  All of which (and more - such as glow plugs and injectors) can lead to big bills.

Your budget will be buying an older, likely higher miles diesel car too, compared to the petrol variant.

I used to love diesels and was a huge advocate but to me, for relatively low miles, they're just not worth the hassle any more.

Herzlos

WIAWSNB said:

Mildly_Miffed said:

WIAWSNB said:

I'm not concerned about a small variation in economy, but my last two Citroen diesels have never, ever dropped below a genuine 50mpg average, and almost always being in the mids.

Hybrids are great by most accounts, but I couldn't bear for a pure-petrol to start delivering below, say, 40mpg

Let's put some numbers to that, shall we?

40mpg @ £1.36/litre = 15.3p/mile
50mpg @ £1.40/litre = 12.6p/mile

Is your budget REALLY so finely balanced that 2.7p/mile, £216/year on 8k, is a showstopper that you "couldn't bear"?

How much is your TOTAL annual motoring cost, including depreciation, maintenance, insurance, VED, MOT, tyres, fuel, parking etc etc?

Let's assume £2k depreciation, £750 legals (insurance, VED, MOT), £1k maintenance/tyres, and £1000 fuel (12.6p) - so a total of £4,750/year = a gnat under 60p/mile.

Your "couldn't bear" threshold is just 4.5% of that.

Good point, well made.

No, ~£200 is not a deal breaker. And I am totally considering a petrol (even Hybrid if I can find one).

When I first started looking at petrol Kugas, however, I was reading 'real life' examples of mid-30's ave, low-30's in town, which shocked me*. If it actually returns above 40mpg average, I'd be happy with that. (Still pants compared to mid-50's, but hey).

I also hate the actual 'filling-up' process, and I'm used to near-forgetting how to do it with my current diesel :-)

*"The sole petrol engine can return up to 44.1mpg..."

https://www.honestjohn.co.uk/realmpg/ford/kuga-2020

WIAWSNB

Herzlos said:

https://www.honestjohn.co.uk/realmpg/ford/kuga-2020

Blimey! The 2L diesel auto is a shocker! 

Goudy

The lines between diesel and petrol efficiency have blurred a bit in recent years.

Modern smaller, lighter petrol cars seem to be getting nearly on par with similar sized diesels of a few years ago.
My petrol 2020 130hp Clio with an automatic gearbox will nudge 60 mpg on a steady cruise at motorway speeds without trying.
A manual Clio diesel with less hp from just a few years ago (2018) would maybe average 65 mpg on the same sort of trips.

Unsurprising really as modern petrols use the same sort of common rail direct injection system as diesels.

Petrol engines do still tend to lag a little behind diesels in heavier, larger cars though. The gulf tends to be a little wider.
Most manufacturers have helped them along a bit with various mild hybrid systems, PHEV systems and one or two have introduced full hybrid systems. Some only offer these sort of vehicles as EV's now.

I was once a big diesel fan.
Everything from a little diesel Citroen AX (60mpg everywhere no matter how you drove it) to vans, 4x4's, estates and hatchbacks which I ran most of them on anything oily and in my opinion, Euro 6 was the death warranty for them. 

Getting the particulates and NOx down to those regulated levels was obviously a challenge to manufacturers, which is why some of them may (or may not) have cheated and when they realised they could no longer get away with it, they lumbered the customer with headaches and expenses for SCR, DPF and EGR systems.
Diesels do tend to have a higher cost of repairs but servicing these days is on par.

My money is on a Hybrid from my next car. I'm quite looking forward to checking the new Aygo X Hybrid out later this year. I only really need a small car and I recently had a love/hate relationship with a 2025 Yaris Hybrid on holiday that was clocking between 2.8 and 3 litres per 100km.
(I loved the consumption figures but hated those red arrows of the energy display screen which shows when the engine is running)

I can't charge at home and I can't see on street rates ever going to fall low enough to make an EV worthwhile, while there is a choice of course.

born_again

Ibrahim5 said:

Have you seen the depreciation on EVs? Fuel might be cheap but the depreciation is off the scale!

You want to see prices EV's are going for at auction.
Prices are rising fast.

People have worked out. Don't by new, buy 2nd hand & reap the savings.

motorguy

born_again said:

Ibrahim5 said:

Have you seen the depreciation on EVs? Fuel might be cheap but the depreciation is off the scale!

You want to see prices EV's are going for at auction.
Prices are rising fast.

People have worked out. Don't by new, buy 2nd hand & reap the savings.

I'm not convinced depreciation on new EVs is that bad.  Most are being sold with big discounts and incentives, but people seem to try to work out depreciation from list price, not discounted price.

I dont think they're that far away from the 50% every three years rule of thumb.

Yes, the way to buy an EV is to by nearly new / used.  Useful savings to be had.

Herzlos

born_again said:

Ibrahim5 said:

Have you seen the depreciation on EVs? Fuel might be cheap but the depreciation is off the scale!

You want to see prices EV's are going for at auction.
Prices are rising fast.

People have worked out. Don't by new, buy 2nd hand & reap the savings.

Great, I'm trying to convince myself not to buy a bargain EV I've been looking at a few days. Are you saying it'd only be sensible to buy it now before the prices go up?