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Should I buy a Used Diesel Car?

Should I buy a Used Diesel Car?


Sales of new diesel cars continue to be torpedoed by the growing tax war being waged against them; is it warranted and does this make a used diesel car a great buy?

It’s hardly a secret that sales of new diesels have been torpedoed by the growing tax war against them.

BUT, that only serves to make them more attractive on the second hand market. The fuel economy advantages they have over a petrol or hybrid, and their power characteristics, which make them by far the most suitable engine for so many cars, mean the arguments for them are as valid today as they have been for the past 15 years or more.

Bear in mind too, that all these tax rises you’ve been reading about, which came into effect this month, apply to new diesels only, not second hand ones.

Front on view of black Audi A3 Approved Used model

Let’s look at some basic figures supporting diesel.

In real world driving, a diesel will give you, at the very least, 50 per cent more miles per gallon than an equivalent petrol, maybe more with the most recent and fuel efficient ones.

Taking the example of a driver doing 8,000 miles a year in a petrol car, with an average of 30 mpg and buying unleaded at the current (April) price of £1.19 a litre, that person will spend approximately £1,430 a year at the pumps. Taking the same annual mileage but with a diesel returning an average of 45 mpg the fill-up cost is around £985, a saving of £450. If you do 10,000 miles a year the saving goes to £550. Those are very conservative estimates of the fuel economy gap too. A 50 mpg average takes your annual cost for 8,000 miles down to £885.

Wad of used £10 notes in an elastic band

And then there are the different characteristics between diesel and petrol.

A diesel gives excellent torque from low revs and for driving a heavy car, towing or for cruising along at higher speeds, but low revs they are perfect. Petrol engines come into their own at higher revs and even with the advances in diesels they are still the smoother engine.

But, take a look at the cars we drive. Seemingly every other person has an SUV (last year they took 31 per cent of the new car market) and you would have to have very deep pockets to consider buying anything other than a diesel version of one in the used car sector. Hybrids are getting better in SUVs, of that there is no doubt, but at the moment there are not too many about and diesel is still better.

If you do high mileage, or use a family car regularly carrying the weight of another couple of passengers in the back, diesel is almost certainly best because the savings in fuel consumption far outweigh the slight penalty in tax.

Any number of market analysts will tell you that buyers should not be scared off second hand diesels; for many drivers they’re the logical choice cost wise, if you buy on finance you’re shielded against any sudden drop in value and if you have a heavier car they’re probably the only sensible choice.

One other thing; if you want a really brilliant car at a bargain price, go for a pre-registered diesel because anything given a number plate before April 1 won’t have the new tax applied, but will have the very latest Euro 6 engine technology.

To give just one example, we have a 2018 Peugeot 2008 1.6 BlueHDi (100bhp) GT Line MPV on sale at £16,990, against a retail price of nearer £22,000. It has an official average fuel consumption of 76 mpg, has CO2 emissions of less than 100 g/km and this car has done just five miles…enough said!

White Peugeot 2008 SUV from the rear at speed going round a sharp bend

Pros and cons of petrol versus diesel.


Probably better for mileages of less than 10,000 miles a year and for city cars/small hatchbacks.



Better for higher annual mileages of 10,000 miles and more, SUVs, MPVs, any tow vehicle.