New car, running costs Diesel versus petrol

[donnybob]

I'm looking at buying a new car. I currently have a diesel that I get 52.3 mpg overall, I have to work out my costs each month so I know that's very accurate.
If I purchase a Petrol I'm going to get lower mpg but the cost per gallon is cheaper as well.
I have to make some assumptions, but assuming petrol is 10p per litre cheaper over 6,000 miles how much could I drop to in MPG for my costs to remain in the same ball park.
As you may guess maths is not my strong point

[FiveKnuckles]

Consider a petrol hybrid.  It'll generate more mpg as you mash the brake pedal and should get more than your current 53mpg.

If it's all about mpg, rip out the extra seats, headlining, spare wheel and lose the belly. 

[Strawberry]

I'm looking at buying a new car. I currently have a diesel that I get 52.3 mpg overall, I have to work out my costs each month so I know that's very accurate.
If I purchase a Petrol I'm going to get lower mpg but the cost per gallon is cheaper as well.
I have to make some assumptions, but assuming petrol is 10p per litre cheaper over 6,000 miles how much could I drop to in MPG for my costs to remain in the same ball park.
As you may guess maths is not my strong point

I have recently changed I have not worked out the MPG for the (very) old car (it doesn't tell me that information), I am noticing I am filling up more often BUT the cost of each fill is a lot less however according to a quick Google old tank 50 litres, new tank 40 litres. Specs obtained from that search is diesel 51MPG, petrol 44-55 MPG Do you need ULEZ compliance, depending where you drive or would like to drive this could be useful in the future.

[RandomGuy99]

Most modern cars are already ULEZ compliant.

"WHAT YEAR CAR QUALIFIES FOR ULEZ?

All cars are subject to the rules – there is no specific year for exemptions (except for historic cars – see below).

ULEZ compliant cars must meet laid down emissions standards. The current criteria for ULEZ compliance is that a car must emit no more than 0.08g/km of NOx and meet the Euro emission standards.

Cars that meet these standards include:

All petrol cars registered after 1 September 2015: The engine must be Euro 4 compliant
All diesel cars registered after 1 September 2015: The engine must be Euro 6 compliant
The above rules also apply to vans, minibuses, motorcaravans and ambulances. Other exempt vehicles include:

All electric cars
All hybrid cars with a Euro 6 engine.
It is worth checking the TfL site because some older petrol and diesel engines will comply with the rules.

For example, many petrol cars registered after 2005 with DVLA (and some from 2001) should be compliant.

For diesel cars, those that are registered after September 2015 should meet the standards.

Certain older vehicles are also exempt from the ULEZ charge, including:

Classic cars that were registered before 1 January 1973
Motorcycles and mopeds that were registered before 1 July 2007
Vehicles with a disabled persons’ badge (until October 2025).
You can find the full list of exempt vehicles on the TfL website."

[RandomGuy99]

Stick with petrol or diesel until the electric car infrastructure is more developed.

I have a diesel which is ULEZ compliant and I pay zero road tax. No worry of battery charging.

[Strawberry]

Most modern cars are already ULEZ compliant.

"WHAT YEAR CAR QUALIFIES FOR ULEZ?

All cars are subject to the rules – there is no specific year for exemptions (except for historic cars – see below).

ULEZ compliant cars must meet laid down emissions standards. The current criteria for ULEZ compliance is that a car must emit no more than 0.08g/km of NOx and meet the Euro emission standards.

Cars that meet these standards include:

All petrol cars registered after 1 September 2015: The engine must be Euro 4 compliant
All diesel cars registered after 1 September 2015: The engine must be Euro 6 compliant
The above rules also apply to vans, minibuses, motorcaravans and ambulances. Other exempt vehicles include:

All electric cars
All hybrid cars with a Euro 6 engine.
It is worth checking the TfL site because some older petrol and diesel engines will comply with the rules.

For example, many petrol cars registered after 2005 with DVLA (and some from 2001) should be compliant.

For diesel cars, those that are registered after September 2015 should meet the standards.

Certain older vehicles are also exempt from the ULEZ charge, including:

Classic cars that were registered before 1 January 1973
Motorcycles and mopeds that were registered before 1 July 2007
Vehicles with a disabled persons’ badge (until October 2025).
You can find the full list of exempt vehicles on the TfL website."

This was something I was quite amazed by when I looked, however there are a lot of older vehicles still in daily use.

[RandomGuy99]

This was something I was quite amazed by when I looked, however there are a lot of older vehicles still in daily use.

And those are the polluting, probably high mileage, knackered ones that they want off the road. They are probably costing their drivers a lot to run in terms of road tax, fuel costs, servicing, so it makes sense to replace them not just because of ULEZ.

Use this checker External Link/Members Only to see if you need to pay charges for driving in different cities.

And ULEZ checker External Link/Members Only

[FiveKnuckles]

@ £1.65 litre diesel, you'd had spent ~£860 for 6,000 miles. (114.7 gallons).
At the current price you'd get 122.12 gallons petrol, equating to ~49 mpg.


Hidden Image/Members Only

[donnybob]

I'm not to bothered about being Ulez compliant
Since I've moved I'm doing a lot of short journeys and my diesel  doesn't like it, regards anti pollution filters etc

[donnybob]

@ £1.65 litre diesel, you'd had spent ~£860 for 6,000 miles. (114.7 gallons).
At the current price you'd get 122.12 gallons petrol, equating to ~49 mpg


Hidden Image/Members Only

Thank you

[RandomGuy99]

I'm not to bothered about being Ulez compliant
Since I've moved I'm doing a lot of short journeys and my diesel  doesn't like it, regards anti pollution filters etc

Just take it for a drive for about 1 hr each week to get it to regenerate the DPF filter.

Do a proximity search on AW and find an SP you have to travel to. You can then regen your DPF filter and have fun at the same time. 

[chrishornx]

I'm looking at buying a new car. I currently have a diesel that I get 52.3 mpg overall, I have to work out my costs each month so I know that's very accurate.
If I purchase a Petrol I'm going to get lower mpg but the cost per gallon is cheaper as well.
I have to make some assumptions, but assuming petrol is 10p per litre cheaper over 6,000 miles how much could I drop to in MPG for my costs to remain in the same ball park.
As you may guess maths is not my strong point

Too many ponderables to be accurate in forecast. If petrol cost 2p a litre and diesel 12p you would save a fortune. If diesel was £1.60 and petrol £1.50 then not so much as a percentage. Plus you are working in miles per gallon yet buying in litres so causing yourself complications calculating.

Maths can't be that weak if you are converting litres to gallons

[scutty brown]

Are there any petrol hybrids that can be easily converted to LPG?

[Jomoore]

Stick with petrol or diesel until the electric car infrastructure is more developed.

I have a diesel which is ULEZ compliant and I pay zero road tax. No worry of battery charging.

Nothing to stop you getting an electric pickup truck, and carrying a diesel generator in the back.  In fact I'm fairly sure you could use red diesel in that, and you'd really save the pennies   

[Blackpool Rock]

I bought a new car around 14 years ago and the diesel model was around £2-3K more to purchase however you then save money in fuel, it does however depend how many miles you do and 6K a year isn't that much.

In theory the diesel is more to buy new but you should get more if you trade it in after X years however that's IF the rules don't change and suddenly they hike up the tax or put an extra environmental tax on diesel at the pumps etc etc

[RandomGuy99]

I bought a new car around 14 years ago and the diesel model was around £2-3K more to purchase however you then save money in fuel, it does however depend how many miles you do and 6K a year isn't that much.

In theory the diesel is more to buy new but you should get more if you trade it in after X years however that's IF the rules don't change and suddenly they hike up the tax or put an extra environmental tax on diesel at the pumps etc etc

Perhaps they'll offer a scrappage allowance for diesel cars?

The target date has moved now, so more time to get the country ready.

[spiralnotebook]

How many years will it take to build the four power stations required to meet demand?

[hairdownthere]

I'm looking at buying a new car. I currently have a diesel that I get 52.3 mpg overall, I have to work out my costs each month so I know that's very accurate.
If I purchase a Petrol I'm going to get lower mpg but the cost per gallon is cheaper as well.
I have to make some assumptions, but assuming petrol is 10p per litre cheaper over 6,000 miles how much could I drop to in MPG for my costs to remain in the same ball park.
As you may guess maths is not my strong point

Petrol hybrid all the way

I run a mild hybrid, getting average MPG of 62, 54 around town.  Previously ran a full electric, it's just not viable where I live and for the journeys I make

[lewisjones23]

Petrol hybrid all the way

I run a mild hybrid, getting average MPG of 62, 54 around town.  Previously ran a full electric, it's just not viable where I live and for the journeys I make

I recently drove 450 miles in one day using a hybrid, total cost in fuel was less than £30.

I can't fault that and will be looking for a hybrid as my next vehicle

[Southernbloke]

Don’t do nearly as much driving as I used to about 5000 miles as opposed to 30000 so I bought myself the vehicle I really wanted as opposed to the most cost effective. I now drive a 4 litre v8 Land Rover which I love .
Never bothered to check what the mpg is ( probably around 15 )

[Blackpool Rock]

Don’t do nearly as much driving as I used to about 5000 miles as opposed to 30000 so I bought myself the vehicle I really wanted as opposed to the most cost effective. I now drive a 4 litre v8 Land Rover which I love .
Never bothered to check what the mpg is ( probably around 15 )

Very nice but do you also have a 2nd vehicle for when it breaks down 

[DastardlyDick]

Very nice but do you also have a 2nd vehicle for when it breaks down 

Good point - the number of relatively new Range/Land Rovers that are breaking down, often catastrophically so, is quite shocking. You can also be stuck roadside for a long time as the permanent 4 wheel drive system means they need a total lift rather than the more usual tilt and slide.

[lostandfound]

Don’t do nearly as much driving as I used to about 5000 miles as opposed to 30000 so I bought myself the vehicle I really wanted as opposed to the most cost effective. I now drive a 4 litre v8 Land Rover which I love .
Never bothered to check what the mpg is ( probably around 15 )

Good choice - the endlessly repeated Internet meme that they break down all the time is overdone! 

[Blackpool Rock]

Good choice - the endlessly repeated Internet meme that they break down all the time is overdone! 

They do always seem to make it into the worst car lists for reliability though along with a number of other supposedly high end marques like BMW and Mercedes

External Link/Members Only

[lostandfound]

They do always seem to make it into the worst car lists for reliability though along with a number of other supposedly high end marques like BMW and Mercedes

External Link/Members Only

High end cars cost a lot to run.

A reason for the rep for unreliability comes about because they've been owned people who can't afford the running costs and skimp on maintenance.

[Southernbloke]

Very nice but do you also have a 2nd vehicle for when it breaks down 

Mine is 23 years old with a rebuilt engine and gearbox. Just had all the suspension and steering rack replaced. When they rebuild the engine they use much better spares than what was originally used in the first place. Good mate of mine did the rebuild and other work. It cost me £2500 to buy it and then spent about £8500 on the work. So for £11000 I’ve basically got a new vehicle which is built to a higher spec than if it had just come off the production line .

[Blackpool Rock]

Mine is 23 years old with a rebuilt engine and gearbox. Just had all the suspension and steering rack replaced. When they rebuild the engine they use much better spares than what was originally used in the first place. Good mate of mine did the rebuild and other work. It cost me £2500 to buy it and then spent about £8500 on the work. So for £11000 I’ve basically got a new vehicle which is built to a higher spec than if it had just come off the production line .

So basically confirms they aren't the greatest as they came off the production line

[PepeMAGA]

My car is getting on a bit, but not keen to change it as to get a more modern car that's as good will cost a fortune. Good mpg, £20 tax make me reluctant to move from a diesel as well.
Probably the most costly thing about it is tyres tbh.

[Southernbloke]

So basically confirms they aren't the greatest as they came off the production line

Absolutely right. Also when you see the price of them new wow !!!!!

[Xtro]

I'm looking at buying a new car. I currently have a diesel that I get 52.3 mpg overall, I have to work out my costs each month so I know that's very accurate.
If I purchase a Petrol I'm going to get lower mpg but the cost per gallon is cheaper as well.
I have to make some assumptions, but assuming petrol is 10p per litre cheaper over 6,000 miles how much could I drop to in MPG for my costs to remain in the same ball park.
As you may guess maths is not my strong point

Avoid a NEW car. Too much depreciation.
The question you should ask yourself is what type of mileage are you doing? Newer diesels don't like short journeys/low mileage due to the technology that helps keep them clean; DPFs, EGRs, AdBlue, etc. Avoid a wetbelt engine if possible or do more oil changes than recommended if you do get one.
You'd need a petrol car that can do 50.2 mpg. (Using the current average; Diesel being £7.40/gallon and Petrol £7.10/gallon).
Long time ago since I went to school, so maybe someone else can calculate to confirm.

And those are the polluting, probably high mileage, knackered ones that they want off the road. They are probably costing their drivers a lot to run in terms of road tax, fuel costs, servicing, so it makes sense to replace them not just because of ULEZ.

Use this checker External Link/Members Only to see if you need to pay charges for driving in different cities.

And ULEZ checker External Link/Members Only

Wrong. I've just updated my Euro4 diesel to a later (same manufacturer and model) Euro 6 diesel and getting 10 mpg less. Every 1,000 miles, I'm paying about £30 more for fuel; for me that's another £360 extra per year.
I might be saving £40 on car tax per year but I'm paying at least £40 more for service items. Tyres will cost more too as they are wider/lower profile.

[RandomGuy99]

Avoid a NEW car. Too much depreciation.
The question you should ask yourself is what type of mileage are you doing? Newer diesels don't like short journeys/low mileage due to the technology that helps keep them clean; DPFs, EGRs, AdBlue, etc. Avoid a wetbelt engine if possible or do more oil changes than recommended if you do get one.
You'd need a petrol car that can do 50.2 mpg. (Using the current average; Diesel being £7.40/gallon and Petrol £7.10/gallon).
Long time ago since I went to school, so maybe someone else can calculate to confirm.


Wrong. I've just updated my Euro4 diesel to a later (same manufacturer and model) Euro 6 diesel and getting 10 mpg less. Every 1,000 miles, I'm paying about £30 more for fuel; for me that's another £360 extra per year.
I might be saving £40 on car tax per year but I'm paying at least £40 more for service items. Tyres will cost more too as they are wider/lower profile.

Did you go for a larger engine in the new car?

[Xtro]

Did you go for a larger engine in the new car?

Same. 2 litre

[berksboy]

Remember there is a lot more the MPG  to think about , one cosly repair can wipe out the savings of a few more MPG. We cant recommend others sites on here but you should look on dedicated motoring sites.Depending on how much mileage you do the difference beween say 55MPG and 35MPG may not not be so much ?

Good luck and plesae let us know what you get and why .

[Blackpool Rock]

Remember there is a lot more the MPG  to think about , one cosly repair can wipe out the savings of a few more MPG. We cant recommend others sites on here but you should look on dedicated motoring sites.Depending on how much mileage you do the difference beween say 55MPG and 35MPG may not not be so much ?

Good luck and plesae let us know what you get and why .

Yeah good point, don't buy any French shit   

[lewisjones23]

Yeah good point, don't buy any French shit   

I vowed never to buy French again after my first car, but one of my vehicles is now French made under a different badge and it has been great

[Watts.E.Dunn]

I vowed never to buy French again after my first car, but one of my vehicles is now French made under a different badge and it has been great

So whats the recommended frog shite then if any:?..

[Roger111]

I recently drove 450 miles in one day using a hybrid, total cost in fuel was less than £30.

I can't fault that and will be looking for a hybrid as my next vehicle

Which car was it out of interest

[Darren101]

Shame he never answered. I'm also curious.

What's people's thoughts on plug-in vs self charging hybrids?  I'm in the market for a new (used) motor.   

[RandomGuy99]

Go with a cleanish diesel.  They are probably pretty cheap to buy second hand as people may he dumping them to buy electric.

But it depends on how many miles you do.  I used to do around 40,000 miles a year now I do less than 3,000. I have a car more for convenience that it being the essential it used to be.

[lostandfound]

Shame he never answered. I'm also curious.

What's people's thoughts on plug-in vs self charging hybrids?  I'm in the market for a new (used) motor.   

Of those two ...

You have cheap or free charging at home or at work? plug-in.

You don't? Toyota self-charging hybrid.

[David1970]

I have a company car, last three cars were, diesel, petrol, and now self charging petrol/electric.
All changes were due to tax considerations, I do 40,000 miles per year.

[Pillowtalk]

I'm looking at buying a new car. I currently have a diesel that I get 52.3 mpg overall, I have to work out my costs each month so I know that's very accurate.
If I purchase a Petrol I'm going to get lower mpg but the cost per gallon is cheaper as well.
I have to make some assumptions, but assuming petrol is 10p per litre cheaper over 6,000 miles how much could I drop to in MPG for my costs to remain in the same ball park.
As you may guess maths is not my strong point

You need to factor in depreciation too if you want to get a reasonably accurate cost per mile.

[Bassman]

I'm not to bothered about being Ulez compliant
Since I've moved I'm doing a lot of short journeys and my diesel  doesn't like it, regards anti pollution filters etc

I was going to mention this as a consideration. I got rid of my old diesel, picked up a newer diesel with a bigger engine, does more mpg. But being newer, it REALLY doesn’t like short journeys. In fact I wish I didn’t bother with a diesel for my mostly very short journeys. Wouldn’t need to worry about dpfs etc.

I’m probably gonna go for a hairy v8 petrol next just for the hell of it before they ban us from
Having personal cars lol.

[Darren101]

Go with a cleanish diesel.  They are probably pretty cheap to buy second hand as people may he dumping them to buy electric.

But it depends on how many miles you do.  I used to do around 40,000 miles a year now I do less than 3,000. I have a car more for convenience that it being the essential it used to be.

I mostly do short journeys / town driving so don't think diesels are great for that. Motorway maybe once a fortnight.   Only do about 10K miles a year. Also in London so have to be ULEZ compliant.

As for charging, electric rates vary at home but think it's cheap at night / over night.  Not sure how to run a power cable out but probably not out of the question. No charging at work.

There are charging points local-ish to me.  I think you pay some sort of subscription to use those?  and don't know if they're fast or slow or what. Are those cheap to use?

Current car is a self charging hybrid. Road tax is only 10 quid a year. I'm guessing that rate is extinct for any new car. 

Oh and I'm currently looking at Japanese, Korean and German brands.  Nothing premium like lexus or Audi / Mercedes. 

[shed]

Isn't Audi and Mercedes German 

[Darren101]

Isn't Audi and Mercedes German 

Yes but they also cost a premium one way or another.

Instead of an Audi, I could look at a Volkswagon, which will cost less.  Same company. Some VWs are said to have the same engine / parts. Insurance and other things will also cost less as they’re potentially less sought after by thieves.

Lexus is Japanese. Same company as Toyota.I like them but they would cost more to buy and they get stolen more.

[timsussex]

petrol v diesel - dont forget servicing costs - most diesels require more frequent servicing - the oil gets contaminated quicker and at £300 a pop not a negligible amount - on the other hand no spark plugs to replace.

Electric can be a lot cheaper but require a charging point at home - so you need a driveway. Charging away from home can be expensive. Battery replacement in many vehicles is expensive/not economic so secondhand electric values not great

Finally if we all go electric where how will the government replace the fueltax/VAT that current cars generate ?

[berksboy]

Yes but they also cost a premium one way or another.

"Instead of an Audi, I could look at a Volkswagon, which will cost less.  Same company. Some VWs are said to have the same engine / parts. "Insurance and other things will also cost less as they’re potentially less sought after by thieves.

Lexus is Japanese. Same company as Toyota.I like them but they would cost more to buy and they get stolen more.

Instead of an Audi, I could look at a Volkswagon, which will cost less.  Same company. Some VWs are said to have the same engine / parts.
They are called VAG Volkswagen Audi Group for a reason ! They use same engines, gearbox , platorm ect on a big range of car including Seat , Skoda Bentley and lamborghini .

[RandomGuy99]

Instead of an Audi, I could look at a Volkswagon, which will cost less.  Same company. Some VWs are said to have the same engine / parts.
They are called VAG Volkswagen Audi Group for a reason ! They use same engines, gearbox , platorm ect on a big range of car including Seat , Skoda Bentley and lamborghini .

VAG group has a lot of brands



Hidden Image/Members Only

[Darren101]

Exactly!  (Didn’t know they owned many of the others or their full name ).   :coolgirl:So I expect quality to be reasonable with a VW without forking out extra for the Audi name, paying more for insurance and servicing, etc. I’m sure some elements of an Audi vs VW will be superior but probably something superficial