Parkers overall rating: 4.5 out of 5 4.5

Miles per pound (mpp) Miles per pound (mpp)

Petrol engines 5.2 - 6.8 mpp
Diesel engines 6.6 - 9.4 mpp
Low figures relate to the least economical version; high to the most economical. Based on WLTP combined fuel economy for versions of this car made since September 2017 only, and typical current fuel or electricity costs.

Fuel economy

Petrol engines 34.0 - 44.1 mpg
Diesel engines 44.1 - 62.8 mpg
  • Efficient diesel engines
  • 330e plug-in hybrid is cost-effective
  • Petrols surprisingly frugal too

How much is it going to cost to run?

As you'd expect for a premium-badged saloon, the 3 Series won't be cheap to run, with higher-than-average servicing costs and more expensive replacement parts. But its efficient drivetrains result in lower fuelling costs, while strong resale values mean lower monthly lease or PCP finance costs when buying.

MPG and CO2

Starting with the diesels, the 318d returns between 55.4mpg and 58.9mpg when fitted with a manual gearbox. With the automatic, BMW claims 52.3-55.4mpg. Step up to the 320d and the figures are 54.3-56.5mpg for the manual, and 53.3-55.4mpg for the auto. Specify xDrive all-wheel drive (auto only), and claimed fuel economy falls slightly to 49.6-52.3mpg. Finally, the 330d claims between 46.3mpg and 47.9mpg.

The petrols aren’t too far behind the diesels for claimed fuel economy. The 320i returns 41.5-43.5mpg, while the 330i offers 40.4-41.5mpg.

Emissions for the 3 Series are pleasingly low across the range. The best performer in the conventional range is the 318d, producing 109g/km of CO2 and 113g/km for automatic and manual gearboxes respectively. The 320d isn’t much worse, producing 115g/km and 110g/km for auto and manual models. Even the auto-only 320d xDrive emits just 118g/km of CO2.

At the top of the diesel range, the 330d emits 133g/km, while the 320i and 330i petrols produce 126g/km and 134g/km respectively.

BMW 330e PHEV mpg and CO2

Putting the regular diesel and petrol models to one side, the 330e plug-in hybrid – which joined the range slightly later in 2019 – has by far the best efficiency figures on paper.

Fuel economy is a claimed 138mpg, while CO2 emissions are just 39g/km. Both figures rely on you making the most of the 41-mile electric-only driving range capability, however, which means keeping the batteries charged up.

A full charge takes 3 hours 25 minutes using a BMW i Wallbox, or 5 hours 40 minutes using a regular three-pin plug. Longer journeys will likely see the overall fuel economy plummet – as you’ll be able to make less efficient use of the electric motor.

Servicing and maintenance

BMW has 150 dealers in the UK with most towns and cities being covered. Customer service is rated highly, but in the JD Power Vehicle Dependability Study, BMW came bottom of all with 181 faults per 100 cars compared with an industry average of 119. For comparison, Audi scored 167 and Mercedes-Benz 136.

BMW servicing isn't based on mileage, but on condition – with the car telling you when it needs a service. There are monthly service plans so you can keep your service history up to date at a manageable, locked-in price. How much you pay depends on the model.

Reliability

  • BMW reliability is well established
  • 3 Series proving dependable in use
  • Three-year warranty as standard

The 3 Series has a good reputation for reliability. According to the Fleet News 50 reliability survey for company cars, BMW comes top and the 3 Series is placed second behind the Audi A4.

The current model uses some new technology which we’ve found to be patchy in operation – such as disconnecting phone connections randomly and even when you come to a stop – but software updates through your dealer should sort this out in time.

It has been subjected to three recalls, which you can check on the GOV.uk website. Otherwise, mechanical components are tried and tested from a vast range of other BMW cars.

Blue 2019 BMW 320d Saloon badge and rear lights

Ongoing running costs

Road tax (12 months) £155 - £490
Insurance group 24 - 42
How much is it to insure?