Buying Guide / 2016 - 2019
BMW M140i (F20/F21)
The last rear-wheel-drive 1 Series. A 340 bhp turbocharged inline-six in a compact hatchback that BMW will never make again.
The last rear-wheel-drive 1 Series. A 340 bhp turbocharged inline-six in a compact hatchback that BMW will never make again.
The M140i is a unique proposition: 340 bhp from BMW's acclaimed B58 inline-six, sent to the rear wheels, in a practical hatchback body. With the F40 M135i switching to front-wheel drive, the M140i has become the definitive modern hot hatch for driving enthusiasts.
Here are the five issues that matter most, drawn from BMW specialist workshops and owner communities across the UK.
Go deeper: Run a free Carwise report on a specific M140i to see which issues may apply to that exact car, plus full MOT history, mileage checks and a personalised buyer checklist.
While the B58 is more robust than the N20/N55 it replaced, timing chain stretch can still occur at higher mileages. Chain rattle on cold start is the early warning sign.
Listen for chain rattle on cold start. Check service history for any timing chain work. The B58 is generally better than predecessors but not immune.
The oil filter housing gasket can leak as it ages, dripping oil onto the exhaust and causing a burning smell. Common on B58 engines over 60,000 miles.
Look for oil residue around the oil filter housing. Check for burning oil smell after driving. Relatively straightforward fix.
The plastic charge pipe between turbo and throttle body can crack or blow off under boost, especially on warm days or with increased boost from a remap.
Inspect the charge pipe for cracks. Listen for whooshing or hissing sounds under boost. Aftermarket aluminium charge pipes are a popular upgrade.
The rear differential mount bushings can wear, causing clunking from the rear under acceleration or deceleration. More common on cars driven hard.
Listen for clunking from the rear when getting on or off the throttle. Check diff mount bushings for cracking. Uprated mounts available from Powerflex.
Variable valve timing solenoids can cause rough idle, loss of power, or check engine lights. Usually fixable by cleaning or replacing the solenoids.
Check for engine warning lights. Test idle quality. VANOS solenoid replacement is a relatively minor job.
The M140i is the sleeper of the BMW range. A 340 bhp turbocharged inline-six in a compact rear-wheel-drive hatchback is a combination BMW will never make again. It flies under the radar with its understated looks but delivers genuine performance car speed.
The B58 engine is one of BMW's best modern units. With proper maintenance, it can handle significant power increases. The M140i offers a unique combination of practicality, performance, and rear-wheel-drive fun that nothing else in its class can match.
Enter the registration for MOT history, mileage verification, known faults for that exact variant, and a Carwise Score.
Check a vehicle nowCompiled from independent expert sources, specialist workshops and BMW owner communities. We are not affiliated with any source listed.
Hero image: Wikimedia Commons