2021 BMW M2 Problems: 6 Known Issues

On the 2019-2021 BMW M2 S55, the M2 Competition shares the S55 engine with M3/M4 and inherits the catastrophic crank hub failure issue. The crank hub (harmonic balancer) is press-fit onto the crankshaft and can slip under high load, especially with upgraded software or track use. When the hub slips, timing is lost and valves contact pistons, destroying the engine. This is the same critical failure point as the F80 M3 and F82 M4. The OEM crank hub has inadequate interference fit. Most failures occur on tuned cars or during hard track use between 30,000-70,000 miles.

On the 2019-2021 BMW M2 S55B30, the S55 in the 2019-2021 M2 Competition and M2 CS uses a plastic valve cover with an integrated, non-serviceable crankcase-ventilation (PCV) diaphragm. Two failures come from the same part. The plastic cover warps or cracks from heat cycling and weeps oil down the back of the head onto the hot exhaust manifold. Separately, the PCV diaphragm tears, which lets the crankcase pull excessive vacuum - the giveaway is a high-pitched whistle or squeal at idle that stops the moment you crack the oil filler cap. Because the diaphragm is integral to the cover, neither failure can be fixed with a gasket alone. Owners report leaks starting before 60,000 miles, with the bulk of cases in the 80,000-100,000 mile range. This is an S55 characteristic - the N55 F87 M2's equivalent oil leak is at the filter housing.

On the 2016-2021 BMW M2, the 7-speed M-DCT dual-clutch transmission in F87 M2 models can develop mechatronics unit failures, causing harsh shifting, failure to engage gears, or transmission fault warnings. The issue is related to the solenoid pack and hydraulic valve body within the mechatronics sleeve.

On the 2020-2021 BMW M2 S55B30, nHTSA recall 20V-666 covers 2020-2021 F87 M2 Competition and 2020 M4 coupes built after BMW relocated part of the engine assembly line. Before the move, the damping element on each fuel injector was fitted by an automated process; afterwards it was fitted manually, and on some engines it was omitted. Without the damper, injector vibration is transmitted into the joint between the fuel line and the high-pressure fuel rail. Over time that connection is damaged and can leak fuel in the engine bay, where an ignition source makes it a fire risk. This is a build-defect recall specific to certain S55 engines, not a general S55 fuel-system wear item - do not confuse it with the diesel HPFP recall 21V-586, which does not cover the M2.

On the 2021 BMW M2, nHTSA recall 21V-554 covers 2021 BMW M2 Competition vehicles whose passenger seat belt retractor's Automatic Locking Retractor (ALR) function - the locking mode used to secure a child seat - may deactivate early, before the belt webbing has fully retracted. A small lever in the retractor may be out of tolerance, so the belt may not hold a child restraint as designed, and in a minor crash where the pretensioner does not fire there may be a slight increase in injury risk. This is a supplier/assembly defect on late F87 production, not a wear item.

On the 2016-2021 BMW M2, the F87 M2 carries its rear differential on rubber mounts, and BMW's service bulletin SI B33 03 18 attributes a hard knocking noise from the rear axle during load reversals to the tuning of the rear differential suspension mount; from 7/2018 BMW's replacement part is a polyurethane mount. The signature symptom is a hard clunk or click from the rear when shifting between reverse and drive, when getting on and off the throttle, or at low-speed manoeuvring, sometimes with a droning vibration at cruise. BMW addressed the complaint through service information rather than a recall, and NHTSA holds a bulletin covering knocking noise and vibration/droning from the rear axle with instructions to replace the rear differential suspension mount. The complaint appears on both manual and DCT cars and is aggravated by track use and tuning.