The 2014 740i with N55 engine is a capable luxury sedan, but suffers from serious oil consumption issues tied to worn piston rings and—less commonly—catastrophic timing chain guide failures. Transmission oil cooler leaks and electronic gremlins round out the owner experience.
Excessive Oil Consumption / Piston Ring Wear
Common · high severity
Typical onset: 60,000-120,000 mi
Symptoms: Burning through 1+ quart of oil every 1,000-2,000 miles, Blue smoke on cold start or acceleration, Misfires or rough idle as fouling progresses, Check engine light for lean/rich codes if rings are severely gone
Fix: N55 piston rings wear prematurely; carbon buildup accelerates the problem. Fix requires full engine-out teardown, new rings, honing cylinders, walnut-blasting carbon, and replacing valve stem seals while you're in there. Budget 25-35 hours labor. Many owners opt for a used low-mileage engine swap instead (15-20 hours) if core is already damaged.
Estimated cost: $6,000-10,000
Timing Chain Guide Failure
Occasional · high severity
Typical onset: 80,000-140,000 mi
Symptoms: Rattle on cold start for first 3-5 seconds, Metallic chain slap from front of engine, Check engine light with cam/crank correlation codes, Catastrophic engine damage if chain jumps timing
Fix: N55 plastic chain guides fracture and the chain stretches. Requires timing cover removal, new guides, tensioner, chain, and often VVT solenoids. If caught early, 12-16 hours labor. If it jumps timing, you're looking at valve and piston damage—add head work or engine replacement.
Estimated cost: $3,500-5,500
Transmission Oil Cooler / Thermostat Leak
Common · medium severity
Typical onset: 70,000-110,000 mi
Symptoms: Red ATF pooling under the transmission bell housing area, Transmission slipping or delayed engagement when leak is severe, Low ATF warning on iDrive, Burnt transmission fluid smell
Fix: ZF 8HP transmission oil cooler and thermostat assembly (integral unit) develops leaks at the seals. Requires dropping the transmission pan, sometimes the subframe for access. 6-9 hours labor plus fresh ATF fill and adaptation with dealer-level scan tool.
Estimated cost: $1,800-2,800
Transmission Mount Failure
Common · low severity
Typical onset: 60,000-100,000 mi
Symptoms: Clunk when shifting from Park to Drive or Reverse, Vibration at idle in gear, Excessive driveline movement under throttle
Fix: Hydraulic transmission mount collapses internally. Replacement is straightforward—support trans with jack, unbolt old mount, bolt in new. 1.5-2.5 hours labor. Use OEM or Lemforder; aftermarket rubber mounts don't last.
Estimated cost: $400-700
Fuel Injector Carbon Buildup / Failure
Occasional · medium severity
Typical onset: 80,000-130,000 mi
Symptoms: Rough idle, misfires on specific cylinders, Hard start or extended crank time, Check engine light with fuel trim or misfire codes, Loss of power under load
Fix: Direct injection N55 suffers intake valve and injector tip carbon buildup. Walnut blasting the intake valves (4-5 hours) helps, but if injectors are failing electrically or mechanically, replacement is required. Index-12 high-pressure injectors are $200-300 each. Replace all six for even wear. Add 3-4 hours labor for injector R&R and coding.
Estimated cost: $2,200-3,500
Electric Water Pump Failure
Occasional · high severity
Typical onset: 70,000-120,000 mi
Symptoms: Overheating warning on iDrive, Coolant warning light, No heat from HVAC at idle (pump not circulating), Whining or grinding noise from front of engine
Fix: N55 uses an electric coolant pump that fails without warning. When it dies, engine overheats in minutes. Replacement is 2-3 hours labor (front-mounted, accessible). Always replace the thermostat and bleed system properly with a Schwaben or Bavarian pressure bleeder. Use OEM pump only—aftermarket units fail within a year.
Estimated cost: $800-1,400
Air Suspension Compressor & Strut Leaks
Common · medium severity
Typical onset: 60,000-100,000 mi
Symptoms: Vehicle sitting low in the morning (one corner or all four), Suspension fault message on iDrive, Compressor running constantly, Harsh ride quality as bags deflate
Fix: F01 air suspension bags crack at the folds, and the compressor wears out from overwork. Strut replacement is 2-3 hours per corner; compressor is 3-4 hours (right rear under trunk floor). Arnott or Bilstein are acceptable aftermarket bags; OEM compressor only. Budget for full diagnostics to pinpoint leaks (often multiple).
Estimated cost: $1,200-2,500 per strut; $1,500-2,200 for compressor
Owner tips
Check oil every 500 miles—N55 will quietly drink a quart between services and starve the chain tensioner.
Use only BMW LL-01 spec oil; 5W-30 synthetics from Liqui Moly, Mobil 1 Euro, or Castrol Edge approved blends.
Walnut blast the intake valves every 50,000 miles to slow carbon-related misfires and ring wear.
Scan for transmission adaptations and fault codes before buying—slipping 8HP is $5k-7k to rebuild.
Budget $2,000/year for unexpected repairs after 80,000 miles; this is not a Lexus LS.
Buy only with full service records and a pre-purchase inspection focused on oil consumption and timing chain noise—otherwise you're inheriting a $10k engine rebuild.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.
Fitment notes: AGM battery required; located in trunk; requires registration/coding when replaced
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Every control module on the 2011-2015 BMW 740i — where it lives, replacement time, and what it takes to program a replacement. Modules marked dealer / factory tool won't work after a part swap alone — budget for programming.
⚠️ Separate modules for driver and passenger. Memory seat, heating, ventilation, massage programming.
Aftermarket tool coverage varies by software version and vehicle build — treat "aftermarket tool" rows as "usually possible" and verify against your tool maker's coverage list before promising a customer. Spot a wrong location or hour? Tell us — corrections ship fast here.
BMW of North America, LLC (BMW) is recalling certain 2013-2015 740i, 740Li, 740Lxi, 750i, 750xi, 750Li and 750Lxi and 2014 ActiveHybrid 7 vehicles. The affected vehicles may have received incorrect replacement left rear taillight assemblies. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) number 108, "Lamps, Reflective Devices, and Associated Equipment."
Consequence: Vehicles with the incorrect left rear lamp assemblies may be less conspicuous to other drivers, possibly increasing the risk of a crash.
Remedy: BMW will notify owners, and dealers will inspect the vehicles and replace any incorrect left rear taillight assemblies, free of charge. The recall began August 11, 2017. Owners may contact BMW customer service at 1-800-525-7417.
Performance
Horsepower
315hp
Torque
330lb-ft
0–60 mph
5.6sec
Quarter mile
14.1sec
Top speed
130mph
Fuel economy (EPA)
City
19mpg
Highway
28mpg
Combined
22mpg
Fuel
Premium Gasoline
Capability & size
Curb weight
4,365lb
EPA class
Large Cars
Wiper blades
F01 generation (2009-2015). Sedan body style has no rear wiper. Uses BMW push-button attachment.
Size-standard part numbers — verify your connector type before buying. Rear blades are model-specific; check the package's vehicle list.
Fuel economy figures are EPA data via fueleconomy.gov (median across matching trims). Performance figures are compiled estimates for the 2014 BMW 740i 3.0L I6 Turbo N55 and can vary by trim.
🔧 Database maintained under the daily editorial review of Chris Hackleman · Master Technician · 20+ years and Jeff Moore · Master Mechanic · 20+ years.