BMW sDrive30i
Modular four-cylinder turbo, the workhorse of the current model range. Very broad power spectrum from 135 to 306 hp. Reliable; watch oil consumption and turbocharger at high mileage.
Roadster Middle Ground: Comfort Meets Performance
258 hp, rear-wheel drive, adaptive chassis — noticeably more bite than the 20i, perceptibly sportier, yet still usable every day. The sensible path to G29 driving pleasure.
Engine Weaknesses 6
Timing chain guide rail can break; chain jump and engine damage follows. More common on early production years and with spirited driving.
Symptoms: Rattling, clattering from the engine, sudden power loss, engine damage
Oil filter housing with integrated oil/water heat exchanger leaks. Coolant loss and overheating risk from about 60,000 km.
Symptoms: Coolant level warning, oil puddle under engine, overheating
A plastic bleed line between the cylinder head and expansion tank becomes porous and breaks. Coolant loss follows; the mounting location is difficult to access, so labour costs dominate.
Symptoms: Dropping coolant level; coolant warning on the instrument cluster; faint sweet smell; no visible puddle under the car
The wastegate linkage on the B48 turbocharger has too much play by design and rattles, especially on cold start and at low revs. BMW offers a repair kit (e-actuator 11655A7A286) as a goodwill measure.
Symptoms: Metallic rattling or clattering from the turbo area on cold start and at idle; disappears at higher revs
As a direct-injection engine the B48 does not wash the intake valves with fuel. Oil vapour from crankcase ventilation and EGR gases form deposits that reduce flow and cause misfires.
Symptoms: Stumbling on cold start; power loss at high revs; rough idle; increased fuel consumption
The crankcase ventilation (PCV) integrated into the valve cover wears out and allows oil into the intake tract. Because PCV and valve cover are a single unit on the B48, the entire cover must be replaced.
Symptoms: Increased oil consumption (>0.5 L/1,000 km); blue smoke on cold start; oil in the intake line; rough idle
Vehicle Weaknesses 8
The mounting bracket for the ride height sensor at the rear axle (passenger side) breaks, causing the car to enter limp mode. Traction control deactivates and cannot be reactivated.
The G29 Z4's soft top tends to creak and twist, especially at high speeds and in varying weather conditions. The hood retaining band is a known sub-optimal solution — BMW has not provided a complete fix.
Early G29 models show noticeable quality issues with panel gaps on the front bumper and bonnet. The panels are not flush — a typical early production issue that was corrected during the production run.
OTA software updates have been described as an Achilles heel on the G29. After updates, vehicle systems can behave incorrectly, or the update fails and leaves the car in a fault state.
On the G29, tail lights can crack internally or allow moisture in. The cause is too-tight panel gaps between the rear bumper and the light unit — BMW uses protective film strips as a temporary fix.
On the M40i G29, the dust covers on the rear differential detach due to manufacturing tolerances and heat expansion. The loose covers rotate and grind against the gearbox casing, producing a metallic whine.
After a few days without driving, climate, mirror and navigation settings reset to factory defaults. Vehicle memory sporadically loses personalisation.
The leather on the entry side of the driver's seat outer bolster shows abrasion marks from normal entry and exit after just a few months. Particularly noticeable with light-coloured leather.
Reports & Tests
10 owner complaints filed with NHTSA (2019–2026). Most reported: Electrical (3), Steering (3), Engine (3).