Despite a drop in new diesel car registrations of almost 30% last year, the value of second hand diesels remained buoyant.
That's according to the latest Auto Trader Retail Price Index report, which recorded an average price of £14,390 for second hand diesels - 3% up on the previous year.
The average price of a second hand alternatively fuelled car increased by 6% to £20,078.
However, it was the petrol sector that made the biggest gain - up 7% on 2017 at an average of £10,550.
The overall average price of a second hand car was £12,542, an increase of 5%.
"2018 was a challenging year on a number of fronts, not least the ongoing economic uncertainty surrounding Brexit, fuel type confusion and new WLTP regulations," commented Auto Trader's Commercial Product Director, Karolina Edwards Smajda.
"However, despite these hurdles, second hand vehicles are not only holding their value but are in fact increasing. It reflects not only the health of the market but, with ever increasing prices, just how fundamental to the buying process finance has become to both new and used cars."