2012 BMW 3 Series Problems: 10 Known Issues

On the 2012 BMW 3 Series N55, bMW SIB 11 14 15 covers F30 3 Series vehicles produced from August 2011 through March 2012. The black plastic engine oil-filter housing may fail and create an internal or external oil or coolant leak; a silver aluminum housing requires no action under the service campaign.

On the 2012 BMW 3 Series N55, bMW recall 14V-176 includes certain E90, E92 and E93 3 Series vehicles with the N55 engine produced through November 2011. Internal leakage at affected VANOS adjustment units can prevent fast adjustment and leave engine emergency mode and the malfunction warning active; this recall is not a generic solenoid-cleaning diagnosis.

On the 2012-2015 BMW 3 Series, bMW SIB 11 03 17 identifies specified F30, F31 and F34 3 Series variants with N20 or N26 engines produced through February 2015. A whining noise from the lower engine area that rises with engine speed can be associated with wear in the timing-chain or oil-pump drive-chain system; the bulletin does not declare every 2012-2015 3 Series defective.

On the 2012-2016 BMW 3 Series N55, the factory plastic charge pipe (between intercooler and throttle body) can crack or blow off under boost, especially on vehicles with increased boost from tunes. This causes immediate loss of power.

On the 2012-2016 BMW 3 Series N55, the N55 in the 335i is a direct-injection engine. Fuel is sprayed straight into the cylinders, so it never washes over the backs of the intake valves, and carbon builds up on them. Oil vapor that gets into the intake adds to the deposits. Over time the buildup restricts airflow and can cause rough idle, misfires, loss of power and lower fuel economy. FCP Euro notes the buildup on the N54 and N55 can get bad enough to almost close off the intake ports and valves.

On the 2012-2016 BMW 3 Series N55, the wastegate actuator and boost solenoid can fail, causing boost control issues, over-boost conditions, or under-boost faults.

On the 2007-2013 BMW 3 Series, bMW bulletin SI B12 02 12 states that various drivability complaints and/or misfire faults on N54 and N54T engines (including E90/E92/E93 3 Series) may be attributed to intake valve and port carbon deposits. Rough idle or misfire codes alone do not establish the cause; the bulletin routes the car through a test plan first and does not set a compulsory cleaning interval.

On the 2012-2016 BMW 3 Series N55, the valve cover gasket can fail, causing oil leaks onto the exhaust manifold which creates a burning oil smell. The PCV valve is integrated into the valve cover, so both are often replaced together.

On the 2006-2015 BMW 3 Series, bMW 3 Series cars with the N52, N54 and N55 engines commonly develop oil leaks from the oil filter housing gasket (OFHG) and the valve cover gasket (VCG). Oil from a leaking filter housing gasket can run down the front of the engine onto the serpentine belt and crank pulley. A soaked belt can slip off or shred, and FCP Euro describes an N54 case where belt debris got past the front crank seal and starved the engine of oil. Valve cover gasket leaks can drip onto the exhaust and cause a burning-oil smell. The leaks get worse over time, and running low on oil can damage the engine.

On the 2012-2013 BMW 3 Series, bMW SIB 01 13 21 identifies 2012-2013 E92/E93 335i, 335is and 335i xDrive Coupe vehicles with N54T or N55 engines in the electric coolant-pump settlement population. The bulletin provides a diagnosis-and-repair path when a warning or fault is present; it does not call for preventive replacement on every N55 3 Series.