Why Are Some Used Diesel Cars Suddenly Worth More?
If you’ve been keeping an eye on the car market, you might have noticed something surprising: while diesel engines seem to be fading out of the new car scene, some used diesel models are actually going up in value. It’s a twist that’s left many drivers scratching their heads. What’s really going on here?
The answer isn’t as simple as “diesel is dead.” In fact, the story is a lot more nuanced—and it says a lot about how car buyers are adapting to a changing market.
What’s Driving the Drop in New Diesel Car Sales?
Let’s start with the big picture. Diesel’s reputation took a major hit after the Dieselgate scandal in 2015, and things haven’t really recovered since. In the first half of 2025, only 58,722 new diesel cars were registered in the UK—a drop of 11.3% compared to the previous year, according to data from the Society of Motor Manufacturers and Traders (SMMT). That’s a far cry from diesel’s heyday.
Car makers are shifting focus, too. Brands like Audi, BMW, and JLR (think Land Rover Defender) still offer diesel options, but most manufacturers are investing heavily in petrol, hybrid, and all-electric models. With stricter emissions rules and looming bans on new fossil-fuel cars, it’s no wonder diesel’s days seem numbered.
Why Are Some Used Diesels Bucking the Trend?
Here’s where things get interesting. Despite the overall decline, certain used diesel models are actually appreciating in value. According to Cap HPI, a respected vehicle valuation firm, a three-year-old Honda HR-V diesel with 60,000 miles is now worth 11.3% more than it was a year ago. The Mercedes CLS is up 8%, and the Ford Mondeo has gained 6.5%.
What’s behind these gains? Dylan Setterfield, head of forecast strategy at Cap HPI, points to a simple truth: there’s still real demand for diesel among high-mileage drivers and dealers. Diesel engines are known for their fuel efficiency, especially on long journeys. And with fewer new diesels entering the market, the pool of used ones is shrinking—making the best examples more desirable.
It’s classic supply and demand. When something becomes harder to find but is still needed, prices can rise, even if the overall trend is downward.
Are All Used Diesels Holding Their Value?
Not even close. The used diesel market is experiencing wild swings. While some models are climbing, others are losing value at an alarming rate. Take the Ssangyong Korando 2.2D: a three-year-old version with 60,000 miles is now worth 24.5% less than it was last year. The Vauxhall Astra diesel has dropped 20.2%, and the Range Rover Evoque is down 12.7%.
What’s causing these sharp declines? In the Korando’s case, uncertainty during the brand’s transition from Ssangyong to KGM has spooked buyers. For the Astra, high-mileage examples are being hit with bigger penalties. And the Evoque’s dip is tied to a sudden increase in used supply after a period of shortage.
So, while some used diesels are hot property, others are struggling—often for reasons that go beyond just the fuel type.
How Stable Is the Used Diesel Market Overall?
Despite the headlines, most of the used diesel market is surprisingly steady. On average, a three-year-old diesel is worth just 2.1% less than it was a year ago. For petrol cars, the equivalent drop is 1.3%. At the one-year, 20,000-mile mark, the tables turn slightly: diesels are down 1.4%, while petrols are down 1.6%.
Philip Nothard, insight director at Cox Automotive International, notes that after the wild price swings of the post-pandemic years—when two- to four-year-old diesels could fetch up to 73% of their original price—things are calming down. Today, those same diesels are worth around 51% of their new price, compared to 58% for petrol cars and just 36% for electric vehicles.
In other words, while diesel values are sliding, they’re doing so in a controlled way. The market isn’t in freefall.
Is There a Shortage of Used Diesels?
Absolutely. The drop in new diesel sales over the past few years means there are simply fewer used diesels coming onto the market. For example, Motorpoint, a leading car supermarket, typically stocks around 5,000 cars—most of them less than four years old. Right now, only about 350 of those are diesels or diesel hybrids.
This scarcity is reflected in the prices you see on dealer forecourts. With fewer options available, the best-kept diesels are holding their value, and in some cases, even appreciating.
Should You Buy a Used Diesel Now?
It depends on your needs and priorities. If you drive long distances and value fuel economy, a well-maintained used diesel could still make a lot of sense. But don’t expect prices to skyrocket. Mark Carpenter, CEO of Motorpoint Group, cautions that while a bump in demand could nudge prices up, the aging pool of used diesels will eventually make them less appealing to buyers who want something nearly new.
There’s also the question of future regulations. Cities across Europe are introducing low-emission zones, and taxes on older diesels are likely to rise. If you’re thinking long-term, it’s worth considering how these changes might affect your running costs and resale value.
What’s the Takeaway for Car Buyers?
The used diesel market is a patchwork of winners and losers right now. Some models are defying expectations and rising in value, thanks to their rarity and ongoing appeal to certain drivers. Others are depreciating faster than ever, often due to brand-specific issues or oversupply.
If you’re shopping for a used car, don’t get caught up in the hype—focus on your own needs, do your homework, and pay close attention to the specific model and its history. The market is stable for most diesels, but the real story is in the details.
And remember: as the car industry continues to evolve, flexibility and a willingness to adapt will serve you well. Whether you stick with diesel, switch to petrol, or take the plunge into electric, the best choice is the one that fits your life—not just the latest trend.