USED MINI BUYING SECRETS

The second generation of BMW’S Mini Cooper S is a riot to drive and more affordable than ever but not without its issues. John Evans finds out more

The Mini is such a friendly little thing that it comes as a shock to discover that the minute your back is turned, the Cooper S of 2007-13 likes to throw its timing chain.

It’ll give you a few hints first, like a brushing noise or perhaps a rattle, from cold at idle. I once owned a Vauxhall Zafira 2.2 that did the same thing. The noise came and went and then one day the pistons and valves shook hands, and that was that. The same will happen to the Cooper S’s engine, although more likely to any fitted before 2011, after which a revised chain tensioner was installed.

That’s right: it’s the hydraulic tensioner rather than the chain that’s the culprit. It doesn’t help that the engine likes a drink – as much as a litre of oil every 1000 miles. That’s a healthy engine, by the way. As the cars get older, experts say the engines are springing oil leaks in most un-bmw-like ways. Fail to keep your eye on the level and a red warning light will be the least of your worries.

The second-generation R56 Cooper S was launched in the shadow of its predecessor, the popular R53 of 2002-06. That earlier version was powered by a Chrysler/roverdeveloped supercharged 1.6-litre engine made by Tritec. Its successor dispensed with that in favour of the new Bmw/peugeot-developed Prince engine, a turbocharged 1.6 making 173bhp, with 177lb ft from 16005000rpm or an overboosted 192lb ft.

Its codename is N14 and it has BMW’S infinitely variable single Vanos valve timing. This is important because, in early 2010, as a result of what at the time BMW doubtless referred to as ‘continuous product improvement’ but what you and I might call a barrage of complaints, it replaced it with a revised version called the N18.

Happily, the uprated engine produced 182bhp and, among other things, had a double Vanos system controlling both intake and exhaust valves to provide a more even spread of torque and lower emissions.

But it also gained mods that looked suspiciously like a ‘fix’ to an unacknowledged problem. Changes included redesigned pistons, an uprated boost line to the turbo, improved crankcase ventilation, a heat shield over the turbo oil pipe and a rigid instead of flexible turbo intake pipe. Experts reckon the N18 is the engine to have. You can identify it by its large plastic cover, while the N14 is ‘naked’. Meanwhile, on the transmission front, the manual gearbox gained an improved clutch for better gear synchronisation.

Bizarrely, the changes were followed a few months later by a full facelift (new bumpers, revised interior, LED tail-lights with pulsating brake lights to indicate the force being applied and additional air intakes). As already noted, in 2011 a revised timing chain tensioner was fitted. Now, at last, the R56 couldn’t spring any more surprises except the one common to any well-bought R56 Cooper S, and that’s just how much fun it is to drive.