Currently reading: Diesel engines: your questions answered
The government is clamping down on emissions regulation, so we've answered your most burning diesel-related questions

London is introducing an Ultra Low Emissions Zone in April of 2019 and understandably, the public have a few questions. So, we've taken it upon ourselves to answer some of the most popular diesel-related, oil-burning questions.

Is it time to give up on the diesel engine? 

I’m changing my car soon. Would it be safest to buy petrol?

Lots of people are thinking like this, just as we move into an era of truly clean diesels. We see no reason not to consider an EU6-compliant, WLTP-era diesel when they go on sale later this year.

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Am I risking a low resale value later if I buy a diesel car now?

So far, there’s no evidence of that. Demand for new cars is falling a bit, but Glass’s Guide says used diesel values — even for VWs from the pre-EU6 ‘defeat device’ era — have been holding up well.

Are all car manufacturers tarred with the same brush as Volkswagen?

We believe not. There have been some rumblings, but the shock of the VW scandal has become conflated with market disappointment about over-optimistic fuel economy results returned using the outmoded NEDC test cycle, soon to be replaced.

Greed, lies and deception - the VW Dieselgate scandal laid bare

What about all those old taxis and vans I see driving around in London?

Surely they’re worse than my car? Possibly, but they won’t be around for much longer. New taxis have to be plug-in hybrids or range-extenders from 2018, and tough new congestion charges are coming this year for all high-pollution vehicles.

I have a 15-year-old diesel car. Should I scrap it?

If it’s healthy and is never driven in urban zones where pollution is an issue, you’re not doing much harm, and you’re saving money.

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Is there anything I can fit to an old diesel to cut pollution?

Probably not. A few accessory companies have tried selling addon gadgets over the years, but there’s no evidence that they work.

Diesel engines: what comes out of your car's tailpipe?

How can I check which pollution standard my car has been built to meet?

The best way is via your car’s VIN number, usually displayed at the base of the windscreen. You may be able to look up its specification on a website, but more likely you’ll have to ask the manufacturer directly. Get a letter, just in case.


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Will car pollution laws get tighter still?

It’s possible, although the combination of tough standards, rigorous testing and proper after-treatment provides pretty good protection for the environment from toxic emissions. One threat may come from a new strain of high-efficiency, high-compression engines that, some experts say, produce fine particulates of their own and will need their own particulate traps.

Volvo boss predicts the death of diesels

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Add a comment…
Citytiger 7 April 2017

Why buy a diesel

what about lack of choice, some manufacturers dont even offer petrol engines in certain models.
Mikey C 7 April 2017

Whether to buy a diesel or

Whether to buy a diesel or not depends on where you live. If you live outside a big city, and do a high mileage, but outside urban areas, then a diesel will still make a lot of sense. If you live in a big city, then I'd stay clear...
typos1 7 April 2017

DPFs can be retro fitted

DPFs can be retro fitted Steve.

I never understood why London Taxis were fitted with large, heavy, old tech diesel engines for the last 15 years - they could have fitted much smaller, lighter and more modern all alloy engines from PSA for instance (a lot of these had DPFs years before other manufacturers fitted them), massively reducing fuel consumption, and emissions.

Mikey C 7 April 2017

London Taxis don't have old

London Taxis don't have old tech engines, the TX4 introduced in 2007 (so accounting for the majority of Taxis) was Euro 4 from the start, and current ones are Euro 6
There are also restrictions in London for all commercial and PSV vehicles, that's why open top buses, for example, are all purpose built, and not old double deckers that have been pensioned off from normal service.