BMW X4 (2014-2018) review - MPG, CO2 and Running Costs

Only diesel X4s are available in the UK, which offer a good blend of power and economy. However, X4 buyers will struggle to justify the premium over the roomier X3, which uses the same engines.

Due to its very heavy circa-1,900kg kerb weight, the X4 could chew through brakes and tyres at an accelerated rate, but that’s unlikely to be a deal-breaker if you’re paying the extra for the X4’s sharper drive.

There’s no hybrid X4, so the most eco-friendly version will remain the cheapest to buy – the X4 20d. BMW claims it’ll achieve up to 54.3mpg when fitted with eight-speed automatic gearbox and emit a respectable 138g/km of CO2 – that’s almost 20g/km less than the next cleanest X4 in the range, the 30d. Go for the manual and the figures are slightly higher at 52.3mpg and 142g/km.

There’s virtually no difference between the 3.0-litre engines in terms of economy and emissions. The 30d returns 47.9mpg and emits 156g/km, while the 35d offers 47.1mpg and 157g/km.

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The X4’s Driver Performance Control also has an EcoPro mode to reduce fuel consumption, with a useful icon on the gauge cluster to show how much fuel you’ve saved while in this setting.

However, the X3 also has all this technology and despite the X4 having a slightly sleeker silhouette than its sister car, its economy figures are no better. The X3 is also cheaper to buy, more practical and there’s a cheaper and more economical X3 18d version. In any rational terms, the X4 is very difficult to justify given the X3 is one of the best mid-size SUVs to drive.

While claimed fuel economy is good for an SUV, and emissions will be appealing to company car buyers, another sticking point with the X4 is road tax. From April, cars costing more than £40,000 face annual road tax of £450 for their first five years on the road, instead of the regular £140. The X4 range starts at just over £37,500, and five of the eight models in the line-up break the £40k mark. If that's a road tax price that's too much to swallow, then the standard X3 will be worth considering instead, as all the 20d-powered models come in below £40k.

Insurance

An expensive and powerful car such as the X4 is never going to be cheap to insure. Groups start at 31 for the 20d, rise to 40 for the 30d and 43 for the 35d. Howeer, the Mercedes GLC Coupe and Range Rover Evoque are about on par with the BMW.

Depreciation

Cars with premium badges such as the BMW tend to hold their value better than those without – and the same goes for economical diesels. So the X4 stands to do well, at least when expressed as a percentage of the original value. It’s still an expensive car though, so expect it to shed more of its list price in terms of outright cash than cheaper rivals.