The fastest non-M car BMW built at the time, slotting between the standard 2 Series and the full M2. The N55 turbocharged inline-six delivers 326 hp through a 6-speed manual or ZF 8-speed automatic to the rear wheels. Widely regarded as one of the best driver's cars of its era, combining strong straight-line performance with a compact rear-drive chassis. Production ran only from 2014 to 2016 before the M240i replaced it.· more· less
Oil gasket leaks are near-inevitableElectric water pump fails without warning
Buy if: You want a compact rear-drive performance coupe with an inline-six and can commit to preventive maintenance on the cooling system and oil seals.
Avoid if: You need low-maintenance ownership or plan to skip oil leak repairs, as neglected gaskets lead to cascading damage.
Gasket between oil filter housing and engine block degrades, leaking oil onto engine and exhaust components · more· less
The oil filter housing gasket is one of the most common failure points on the N55 engine. The rubber gasket hardens and shrinks over time due to heat cycling, typically beginning to seep between 60,000 and 100,000 km. Oil drips down the engine block and can reach the exhaust manifold, creating a burning smell and potential fire risk if left unaddressed. On the N55, the oil filter housing sits above the exhaust side, making leaks particularly problematic. The repair involves removing the intake manifold on some configurations, adding labor time. At an independent specialist, expect 400-600 euros (2-3 hours labor plus gasket). BMW dealers typically charge 600-900 euros. This repair is often combined with the valve cover gasket to save on labor overlap. Ignoring this leak can damage the serpentine belt and alternator below.
Valve cover gasket leak
€500 - 1,2002 of 7
Valve cover gasket deteriorates from heat, causing oil seepage along the top of the engine · more· less
The valve cover gasket on the N55 is a known wear item that typically starts leaking between 80,000 and 120,000 km. The gasket is a separate part on the N55: the M235i F22 catalogue lists cover 11127570292 and gasket 11127587804 individually, so a leak does not automatically mean buying a whole valve cover. Shops often replace both together anyway, because the plastic cover warps with age and a warped cover will leak again on a new gasket, but ask which parts a quote actually covers. Symptoms include oil smell from the engine bay, visible oil on the engine block, and in advanced cases oil dripping onto the exhaust. At an independent shop, the repair costs 500-800 euros with a new cover and gasket, and less if the existing cover is flat and only the gasket is renewed. BMW dealers charge 800-1,200 euros. Many owners combine this with the oil filter housing gasket replacement to save on labor, as there is some overlap in access.
Electric water pump failure
€600 - 1,2003 of 7
Electric water pump fails abruptly, causing rapid overheating with no gradual warning · more· less
The N55 uses an electrically driven water pump that is known to fail between 100,000 and 150,000 km. Unlike a mechanical pump that may leak or whine before failing, the electric pump simply stops working, and the engine can overheat within minutes. BMW does not include the water pump in the standard maintenance schedule, so many owners are caught off guard. The thermostat is electronically controlled and often fails around the same time, so replacing both together is standard practice. The OEM water pump costs approximately 350-450 euros, and the thermostat adds another 100-150 euros. With 3-4 hours of labor, total repair at an independent specialist runs 600-900 euros, while a dealer charges 900-1,200 euros. Preventive replacement around 100,000 km is strongly recommended by specialists.
Charge pipe crack or blow-off
€150 - 5004 of 7
Plastic charge pipe between intercooler and intake cracks under boost pressure, causing power loss and limp mode · more· less
The N55 comes from the factory with a plastic charge pipe that routes compressed air from the intercooler to the intake manifold. Over time, heat cycling and boost pressure cause the plastic to become brittle and crack, resulting in a boost leak. Symptoms include sudden loss of power, limp mode, and a hissing sound under acceleration. This failure can happen at stock boost levels, though it is more common on tuned cars. On a completely stock M235i, it typically occurs after 80,000-120,000 km. The OEM plastic replacement costs around 80-120 euros, but most specialists recommend upgrading to an aluminum aftermarket charge pipe (150-250 euros) that eliminates the issue permanently. Total repair cost including labor is 150-300 euros with an aftermarket pipe, or up to 500 euros at a dealer with OEM parts.
Valvetronic eccentric shaft or servo motor failure
€800 - 2,5005 of 7
Eccentric shaft gear wears due to poor lubrication, causing rough idle or no-start condition · more· less
The N55 Valvetronic system controls valve lift electronically via an eccentric shaft and servo motor. The eccentric shaft gear can wear prematurely if oil changes are stretched too far, as the oil squirter that lubricates the gears has a very small passage that clogs easily. The servo motor itself can also fail, though this is less common. Symptoms range from rough idle and reduced power to a complete no-start condition. Forum reports suggest this occurs on roughly 5-10% of N55 engines, typically between 60,000 and 120,000 km. Servo motor replacement alone costs 400-700 euros at an independent shop. If the eccentric shaft is also damaged, the repair escalates to 1,500-2,500 euros due to the extensive labor (5-6 hours) needed to access the shaft. Maintaining strict oil change intervals of 10,000 km or less significantly reduces the risk.
VANOS solenoid fouling
€200 - 5006 of 7
Variable valve timing solenoids become clogged with oil deposits, causing rough idle and reduced performance · more· less
The VANOS solenoids on the N55 control variable valve timing and are prone to fouling with carbon and oil deposits, particularly when oil changes are not performed regularly. Symptoms include rough idle, slight hesitation on acceleration, and occasionally a check engine light. The solenoids typically start losing efficiency around 80,000-120,000 km. Cleaning the solenoids is possible and costs around 100-150 euros at a specialist, but replacement is often recommended for a lasting fix. A pair of new VANOS solenoids costs approximately 100-200 euros for parts, with 1-2 hours of labor bringing total replacement cost to 200-500 euros. This is largely preventable with regular oil changes using quality synthetic oil.
Wastegate rattle
€150 - 1,8007 of 7
Turbo wastegate actuator arm develops play, causing metallic rattle at idle and low RPM · more· less
A common complaint on N55-equipped cars is a metallic ticking or rattling noise from the turbocharger area at idle. This is caused by play in the wastegate actuator arm where the circlips do not clamp the joints tightly enough. The rattle is most noticeable at cold idle and often disappears under load. While this is largely a cosmetic/noise issue and does not typically affect performance or turbo lifespan, it can be annoying. Some BMW dealers have classified this as a normal characteristic of the engine. If the rattle is minor, no action is needed. For significant rattle, the actuator arm can be tightened or shimmed at a specialist for 150-300 euros. If the wastegate itself is worn and affecting boost control, a turbo rebuild or replacement runs 1,200-1,800 euros.
Reliable for a performance car, but oil leaks and cooling need attention
The N55 inline-six is fundamentally a robust engine that can exceed 200,000 km with proper maintenance. However, oil gasket leaks (filter housing and valve cover) are near-certain by 100,000 km and should be budgeted for. The electric water pump is the most critical failure to watch for, as it fails without warning and can cause expensive overheating damage. Most other issues are moderate in cost and preventable with regular maintenance. Manual gearbox cars are slightly simpler; the ZF 8HP automatic is generally very reliable, and while BMW calls its fluid a lifetime fill, ZF's own guidance is a change at 150,000 km, with shorter intervals only under the severe use conditions it specifies.
Service history
Complete BMW dealer or specialist records essential. Verify oil changes every 10,000-15,000 km. The N55 is sensitive to extended oil intervals.
Tires
Check tread depth, age (date codes), and uneven wear. Rear tires wear faster on RWD. Standard size is 225/40R18 front, 245/35R18 rear.
Cold start
Start the engine completely cold. Listen for wastegate rattle in the first 30 seconds and watch for any warning lights.
Test drive
Minimum 30 minutes including spirited acceleration. Check for smooth power delivery, no hesitation, and consistent boost.
Specific for this vehicle
Inspect engine for oil leaks
Look at the oil filter housing area and along the valve cover edges. Any oil residue or wet spots indicate gasket leaks that need repair.
Check coolant level and water pump operation
Coolant should be at the correct level with no discoloration. After driving, verify the electric fan kicks in. Low coolant or overheating history suggests water pump issues.
Listen for turbo wastegate rattle at idle
With the engine warm at idle, listen for metallic ticking from the turbocharger area. Minor rattle is common but heavy knocking suggests worn actuator.
+ 3 more checksShow less
Test full-throttle acceleration for charge pipe integrity
Under hard acceleration, listen for hissing or sudden power loss that could indicate a cracked charge pipe. The car should pull smoothly to redline.
Check for signs of tuning or modification
Many M235is have been tuned. Look for aftermarket downpipes, intakes, or intercoolers. Request an ECU flash count check via BMW diagnostic software.
Verify transmission fluid has been changed (automatic)
If equipped with the ZF 8HP, ask for proof of fluid changes. BMW calls it a lifetime fill; ZF specifies a change at 150,000 km, sooner under severe use such as towing or heavy stop-start work.
Recalls and Technical Service Bulletins
Head airbag inflator weld joint failure (European records cover 2013-2014 production, and the French notice a narrower February to April 2014 population)Verify completed
Contact BMW with the VIN to verify all recalls have been completed. The head airbag campaign is the important one, and its published scope varies between registers: the EU Safety Gate entry covers 2013-2014 production while the French notice names a narrower February to April 2014 population, so the VIN decides. The fuel pump nickel plating campaign that appears alongside it is recorded as a BMW of North America action; ask the dealer whether any European equivalent applies to the car rather than assuming it does.
Warranty Status
Factory warranty (2 years, 3 years in the UK)Expired on all M235i models
BMW extended warrantyUnlikely to be available due to age
Rust perforation warranty (12 years)May still apply on 2014-2016 models until 2026-2028
All BMW M235i F22 models are outside their original factory warranty, which ran two years in most European markets and three years in the UK. Extended warranties from third parties may be available but typically exclude pre-existing oil leaks. The 12-year rust perforation warranty may still be active on some cars.
Sources: Research draws on model-specific owner forums and owner communities, recall information from official authorities, German automotive press, and multiple workshop cost references cross-checked against each other.
This report is for informational purposes only and does not constitute professional advice. Estimates may be inaccurate. Always have a qualified specialist inspect the vehicle before purchase. We accept no liability for decisions made based on this information.
