Though a brilliant driving machine, the 335i performed far from flawlessly…

So presumably I’d recommend it unreservedly and last one to the BMW showroom’s a sissy? Well, not so fast. As brilliant a driving machine and as beautifully wrought a family conveyance as it is, the 335i performed far from flawlessly.

The first glitch was with the infamous iDrive. I’m actually quite a fan of the oft-maligned gizmo that allows you to toggle between hi-fi, climate, satnav and Bluetooth at the push and woggle of the small control wheel. It’s a darn sight easier, and hence safer, than trying to locate myriad minuscule buttons somewhere down in the centre console. But my enthusiasm was dented when scarcely a month after the 335i arrived, the screen filled with the legend ‘BMW’ and nothing else. Whatever I did with the little wheel, it just span uselessly. Deprived for several days of sounds, control of my climate, satnav and hands-free, I wasn’t a happy bunny, and even less so when the local dealership, Wollaston BMW in Northampton, concluded that only a ‘complete software and control unit update’ would cure it. This, I was told, would require ‘the special machine’ and that wasn’t available till the following week. Oh, and it could take two days.

In fact it took just a day and the iDrive was restored. There then followed several months of unadulterated driving pleasure. The 302bhp twin-turbo 3-litre straight-six, which had just been voted Engine of the Year, had oodles of creamy torque absolutely everywhere. It was matched with a chassis that was deliciously taut and controlled; the slightly lowered M Sport suspension, 18in M alloys and Bridgestone Potenza runflats put you on intimate terms with the road surface. The steering was pleasingly weighty, responsive and confidence-inspiring. Even without deactivating the DTC you could sense lovely little slip angles developing at the rear as you felt your way around the limit. And with the rising snarl of the engine and the heavy but satisfying action of the six-speed manual box, the 335i had bags of character. All of which meant it was engaging to drive at any speed, but quite brilliant when you were really pressing on. In terms of cross-country pace and sheer involvement, I reckon the 335i isn’t far off the current M3.

In the summer it faced one of its sternest challenges: the family holiday. We’d booked a cottage at the far end of Cornwall and we’d decided to take two of the dogs as well as three kids and all their associated clobber. It was a squeeze but, with the addition of a roof box, we managed it. The boot’s not huge, but it’s well-shaped (it’s also a doddle to flatten the seats for large loads) and there’s a surprising amount of room for back seat passengers – enough for two teenagers and one 11-year-old without Bovingdon-style tantrums. The only fly in the sunscreen was that right on the morning of departure the onboard computer announced that a service was due – despite two thousand miles earlier saying that it wouldn’t be due for another 6000 miles. Doh. Since the computer also said the oil level was slightly low (there’s no manual dipstick) we topped it up and booked it in to Wollaston on our return.

The ‘Fast Lane’ oil-change service is claimed to take just 90 minutes and you get a voucher for a drink and a bite in the cafe while you wait, though in fact I was waiting for closer to two hours and forewent the advertised wash and wax (for the car, that is) to save time, but the cost of £162.95 was reasonable. Overall the service from Wollaston was excellent. Which was just as well, for my love affair with the 335i was about to face its biggest test.

Though often driven in the spirited fashion for which it was designed, the 335i had had a pretty cushy life compared with certain cars on the fleet, so it was a surprise when in mid-September after around 16,500 miles and just a month after its service, an engine fault warning appeared on the dash and the car went into reduced power mode. Surprise turned to consternation when Wollaston suspected a turbo fault and consternation turned to shock when they said they’d have to replace both turbos because the wastegates were prematurely worn, causing them to stick open. The car was with them for more than a week, though I did get a 320d Touring replacement and regular phoned updates. Seems it’s a big job replacing the turbos – in fact it’s an engine-out job – and since it’s all under warranty it cost the manufacturer more than two grand. Gulp.

After I reported the saga, three other 335i owners emailed to say they’d also had turbo failures, in one case at just 8000 miles. I put all this to BMW GB and a spokesman said there had been a ‘very small number of issues with wastegates sticking’. In three cases they’d replaced the actuators that controlled the wastegates. Overall they’d replaced fewer than ten turbochargers on 335is for whatever fault, which, he said, suggested they were ‘generally very reliable’. There was no service campaign or recall on the actuators or turbos. BMW’s feeling was that these isolated cases were due to ‘material failure, possibly due to manufacturing tolerances’.

So there you go. Please keep writing in with your experiences of this engine, and we’ll keep reporting them. If BMW is right, once these few cases have been rectified, we’ll have nothing to fear from the twin-turbo six and we can all go on enjoying its brilliant performance – and also its quite remarkable economy. We regularly saw over 27mpg, and over Christmas, when I was driving particularly carefully on account of the 335i being laden with children, dogs, booze and pressies, we saw 28.5mpg.

Living with it for nine months revealed some minor flaws – the fob from the plastic ‘key’ dangled exactly where my left knee wanted to be; the headlights weren’t quite as strong as they might have been on full beam; the interior wasn’t as classy as an equivalent Audi’s, though the Lemon Dakota leather stood up well; the DAB radio sometimes struggled to find a signal; there was the occasional clonk from the driveline if you weren’t super-smooth with the clutch. But in every other respect it was better than painless, it was a positive joy to live with.

Our 335i had one more minor wobble to throw, when the satnav froze while navigating me through Hammersmith one evening in mid-November. Stopping and restarting the engine fixed that. Otherwise it was back to its brilliant best right up until the day in late January when it finally went back. I scrolled through the computer readout one last time: 25,510 miles; 28.2mpg; 6000 miles to the next service; oil just below the max. I took it for one last drive, and it sounded as dreamy and surged forward as effortlessly as the day it arrived. The ride still jiggled and thumped over the worst urban roads, but I realised I’d learned to live with the runflat tyres, which by now were worn down but still (just) legal.

While the faults can’t be glossed over, I still want to tell the world what a brilliant car this is. Cross-continental drives, trackdays, family duties – it excelled at them all. That last drive was to find a hand car- wash. When the guy had finished leathering the 335i he stood back and nodded his head slowly in appreciation. ‘Great car, mate,’ he said. I couldn’t argue with that.