Diesel cars are on the way out. The ban on the sale of new petrol and diesel vehicles may have been delayed by five years, but it will still come into force in 2035.

Unless the goalposts move again, from then, no internal-combustion-engined cars will be sold, although it’s unclear if hybrids with significant electric ranges will be exempt.

Long before the ban, diesels have been declining in popularity. Last year, they made up just 3.8% of the new car market. A decade ago, that figure was 49.8%.

Emissions scandals, the growing number of low-emission zones, and incentives to choose electric cars have all seen diesel’s reputation diminish and sales drop rapidly.

So, should you still think about buying a diesel tow car in 2024? Do they still make good choices for caravanners looking for the best car to tow a caravan?

Buying a diesel tow car: old or new diesel

The first point to consider if you’re thinking of buying a diesel tow car is that all diesels are not the same. While older ones produce significantly more particulate matter and nitrogen oxides (NOx) than petrols, under the most recent emissions standards, that’s not the case. Diesels that meet the Euro 6 standard must emit no more than 0.08g/km of NOx.

That’s only a slight difference to the 0.06g/km permitted for petrols, and a big drop from the 0.18g/km allowed for diesels under Euro 5. Particulate levels are the same for diesel and petrol vehicles.

Since the ‘Dieselgate’ scandal showed that the Volkswagen Group was cheating emissions regulations, there has been understandable suspicion as to whether the official tests can be trusted.

However, the official laboratory tests are now checked against on-the-road tests, making it much harder for manufacturers to find a way around the rules.

The Euro 6 standard came into force in September 2015, so any diesel registered after this date should be much cleaner than an older one. That’s why Euro 6 diesels are permitted to drive in low emission zones such as the London ULEZ without a charge. This isn’t to say that a modern diesel vehicle doesn’t pollute or that an electric car isn’t better for local air quality. However, the idea that petrol is a much cleaner choice than diesel just isn’t true if you are looking at cars made over the past eight or nine years.

The market for diesels

The new and used car markets tend to behave differently. While diesel is much less popular among new car customers, buyers of used cars haven’t been so quick to change to alternatives.

According to the used car market experts at Cap HPI, it takes an average of 47 days to sell a used diesel vehicle, which is only two days more than a petrol car.

For now, there’s still plenty of choice, too. At the end of February this year, 32.2% of the cars on sale through the used car website, Autotrader, were diesel powered.

Demand for diesel tends to be strong among SUV buyers, especially those looking for large and heavy cars – many of which will be well suited to towing. After all, the best SUVs for towing are a popular choice for caravanners, available in both two-wheel- and four-wheel-drive.

That means resale values remain healthy for many diesels. For example, What Car? predicts that the Volkswagen Touareg 3.0 petrol will be worth 45% of the original price after three years and 36,000 miles. The 3.0-litre diesel will be worth 46%.

Over the next few years, low new car sales will reduce the number of used diesel models to be found on the forecourts, but reduced supply does tend to keep resale values looking healthy.

Diesel versus alternatives

A few years ago, diesel was the default choice of engine for an efficient tow car. Broadly speaking, petrol vehicles were either lacking in pulling power, too thirsty, or both. Hybrids were often hampered by low towing limits, or simply weren’t approved to tow at all.

Now, caravanners who are choosing a tow car will find the best full and plug-in hybrids compete closely with the top diesels as towing options. Electric power delivers excellent performance from a standstill, making up for the peakier power delivery of the petrol engines usually employed in hybrids.

Electric cars have also come a long way. The likes of the Kia EV6 and the Genesis Electrified GV70, for example, tow very well indeed, providing impressive stability and strong performance.

Genesis Electrified GV70 Sport
The Genesis Electrified GV70 Sport

However, the electric cars we’ve tested generally have a range of around 100-130 miles while towing, and recharging when you’re hitched up (see: hitching a caravan to a car for our guide to doing this) is much more problematic than topping up the batteries without a trailer to worry about.

For long journeys, especially while you are towing, the real-world fuel economy achieved by a good turbodiesel engine is compelling. Having towed with both the full hybrid and the diesel versions of the Kia Sorento, we found the diesel returned the better fuel economy by around 5mpg.

Although plug-in hybrids can return excellent economy while towing, so long as the battery has a healthy charge, economy worsens once that charge runs low.

As a rule, diesels will be more economical and produce less carbon dioxide on a long towing trip. You can expect the economy of a diesel vehicle to be quite consistent while towing, whether you are travelling 30 miles or 300 miles.

Final thoughts on buying a diesel tow car

We’re not here to tell you which type of car to buy, and we’re not saying hybrids and electrics don’t have advantages over diesel.

But caravanners’ needs are different from those of the average car buyer. Long towing journeys place tough demands on a tow car, and diesels still meet those challenges well.

The best turbodiesels are economical on long trips, which is better on your pocket and means less carbon dioxide is released.

Although new car sales have collapsed, there is still demand for diesels on the used market, and should be for some years to come. You’re not throwing your money away if you buy a modern diesel, whether you shop on the new or the used market.

We’d be inclined to avoid pre-Euro 6 cars, budget allowing, as these are worse for the environment than the latest models. But there’s still a place for diesel tow cars.

After sorting your car of choice, it will be time to protect it – this is something that a good steering wheel lock can help with.

Image: Getty Images

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