BMW 3-Series (2015-2018)

By Jonathan Crouch

Models Covered

4dr Saloon / 5dr Touring Estate (318i, 320i, 330i, M3, M3 CS / 318d, 320d, 330d, 335d)

Introduction

The 3 Series has always been the heart of the BMW brand, traditionally responsible for a quarter of the company’s global sales and the benchmark against which every mid-sized premium executive car measures itself. At its original launch in 2012, the sixth generation version set the bar higher still, but key competitors responded in kind, necessitating the arrival of this cleverer, more efficient facelifted version in 2015, complete with a rejuvenated range of engines, cutting-edge technology and the option of all-wheel drive. It’s a strong proposition for the used market buyer.

The History

For over four decades, one car has dominated the segment it first invented. BMW’s 3 Series established the market for sporting premium mid-sized executive cars way back in 1975 and it’s been a benchmark in this sector ever since. Never though, has the competition been stronger, opposition that back in 2015, this much improved sixth generation version had to be good enough to face down.

What was needed at this time was more than just a wash ‘n brush-up – and we duly got just that. For a start, nearly all the powerplants on offer in this revised model were completely new, some of them real headline-makers. Like the three cylinder MINI-derived engine. The Plug-in Hybrid variant capable of nearly 135mpg. And a diesel engine able to return nearly 75mpg and sub-100g/km CO2 emissions. There was stunning performance on offer too: a six cylinder 335d diesel with almost as much torque as a Lamborghini V12. And a petrol 340i variant boasting the kind of power previously limited to BMW’s M3 street-racer.

The changes to this updated MK6 model weren’t only about performance and efficiency though. There were sharper looks and clever LED headlights, plus this car was the first in its segment to support the much faster data transmission speeds of 4G LTE as part of the class-leading smartphone connectivity that BMW knew its business buyers would want. On top of that, almost countless little tweaks were made in polishing the class-leading handling dynamics, with the classic rear wheel drive configuration joined on selected models by an xDrive 4WD option for those wanting it. On paper then, what was offered here seemed to be a very complete package – and sure enough, it sold well until the car was finally replaced in early 2019.

What To Look For

Our owner survey did reveal many satisfied users of this car but inevitably, there were a few issues reported. Obviously, a fully-stamped service history is vital. This car uses complex engines and only regular and appropriate maintenance will see them go the distance. The biggest potential for financial grief down the track is the variable valve-timing mechanism (VANOS, in BMW-speak) which is vital to the engine's efficiency and performance but can suffer if that maintenance has not been observed. The tiny oilways that help make up the VANOS system can become clogged with dirty oil and this won’t be cheap to put right. In fact, early-build 3-Series with the six-cylinder engine were actually recalled over VANOS issues.

It seems the oil-feed line to the VANOS unit on these engines could become loose, leading to a loss of oil pressure and sending the car into ‘limp-home’ mode. And you won't see a tell-tale oil leak from the loose fitting, because it was an internal leak that caused the dramas. According to BMW, a lack of lubrication in the booster's vacuum pump could lead to a loss of braking assistance. The brakes would still work, but would require a much bigger push on behalf of the driver. Otherwise, it’s just the usual things. Insist on a fully stamped-up service record and check the alloys for scratches and scuffs.

On The Road

The basic formula here hasn’t changed much. Front engine, rear wheel drive, and near perfect 50:50 weight distribution have defined the 3 Series to date and this one doesn't deviate too far from that script, although BMW has of late been doing rather well in this country with its growing line-up of xDrive all-wheel drive versions. But it’s in standard rear- driven guise that this car really seems to shine in comparison to its mid-sized executive segment rivals. Tweaks made to the suspension and steering for the 2015 MK6 model facelift made this car even more rewarding to drive and the manual and automatic gearboxes (also revised at this time) improve your feeling of connectedness still further.

As usual in models from this era, BMW included a ‘Drive Performance Control’ system across the range allowing you to change steering and throttle settings (plus on automatic models gearshift timings), to suit the way you want to drive. Get a car whose original owner specified the ‘Adaptive M Sport suspension’ and the DPC set-up will alter the damping too. Under the bonnet, much changed as part of this MK6 model’s 2015-era facelift, especially in the petrol line-up that for this improved design starts with a 136bhp three cylinder 1.5-litre MINI-derived engine in the base 318i variant. Next up is an in-line four cylinder 2.0-litre powerplant, developing 184bhp in the 320i and 252bhp in the 330i. Also improved as part of this facelift package was the six cylinder 3.0-litre unit in the potent 340i, which offers 326bhp. Most original buyers though, focused on the 2.0-litre four cylinder diesel models. Their TwinPower Turbo unit comes in 116, 150, 163 or 190bhp states of tune; the 163bhp 320d ED Plus model we’d recommend is capable of up to 74.3mpg on the combined cycle and as little as 99g/km of CO2. This variant sits below a 3.0-ltre six cylinder powerplant offering either 258bhp or 313bhp in the top 330d or 335d variants.

Overall

BMW has rarely had to work as hard on a mid-term facelift as was the case with this post-2015-era 3 Series model – but it paid off. In a world where driving can so often be such a mechanical, joyless activity, this BMW remains involving in a way its competitors are struggling to match. In that respect at least, this version remains a benchmark for its period.