"Is the 3 Serisi 318i reliable, and what should you check?"
When buying a used BMW 3 Series 318i 2009 (E90 / E91 / E92 / E93 / facelift), the most frequently mentioned issue is oil leaks from gaskets and seals. Ignition problems and misfires are also commonly reported.
Engine: N43
N43B20A · 318i · Used in this car from 2008-2013
Strengths
Very economical for its displacement
Quite peppy and responsive unit
Watch-outs
Frequent fuel system failures
Catalyst sensitive to poor fuel
Very picky about oil quality
Known engine issues
Injectors and high-pressure fuel pumpThe weak point of this engine is the high-pressure fuel pump and short-lived Siemens piezo injectors. They cannot tolerate poor fuel and can fail at almost any mileage. Note that later revisions of these components are much more reliable than predecessors.
Catalytic converterThe exhaust system has a storage catalyst with a nitrogen oxide sensor, and they burn off contaminants only during prolonged high-speed driving. If this system fails, repair is very expensive, and owners often delete it.
Timing chain and VVT adjustersThe VVT adjusters are quite reliable but require quality oil and maintenance. Every 60,000 km their valves need cleaning and seals need replacement, otherwise they will rattle quickly. The chain itself lasts long; only guide rail failure occurs at low mileage.
Listed from most frequently reported, each with its source.
Oil leaks from gaskets and seals
Often reported
Oil leaks from seals such as the oil filter housing gasket or valve cover gasket and connection points are frequently reported; seepage or more significant leaks may develop over time.
Engine Bay
Ignition problems and misfires
Often reported
Periodic ignition problems and misfires are reported; symptoms include a flashing check engine light, power loss, and rough idle.
Engine Internal
High oil consumption
Often reported
Many owners of the 2.0 143 HP (N46 engine) report higher than normal oil consumption: the engine can consume hundreds of grams of oil every 1000 km. Documented recurring causes include worn valve stem seals and, in more severe cases, worn piston rings/pistons.
Engine Internal
VANOS / Valvetronic issues and vibrations
Often reported
Deposits or faults can occur in the VANOS variable valve timing and Valvetronic systems, leading to vibrations, idle fluctuations, power loss, and the check engine light coming on.
Engine Internal
Timing chain tensioner and plastic guide wear
Often reported
In N46 engines, timing chain stretch and wear of the plastic tensioner/guides are reported; this can cause metallic noises and risk of engine damage.
Timing chain
BMW 3 Serisi 318i technical specs
BMW 3 Serisi 318i (2009): boot 460 L; fuel use 6,3 l/100 km (urban 8,1 l/100 km · extra-urban 5,3 l/100 km); 0–100 in 9.1 s.
Boot capacity
460 L
Fuel consumption
6,3 l/100 km (urban 8,1 l/100 km · extra-urban 5,3 l/100 km)
What should I look for when buying a BMW 3 Series 318i?+
When buying a 2009 318i, check the service history, test drive, and look for engine/transmission warning lights. The most commonly reported issues are: oil leaks from gaskets and seals; ignition problems and misfires; high oil consumption.
What are the common problems of the BMW 3 Series 318i?+
The most frequently reported issues are: oil leaks from gaskets and seals; ignition problems and misfires; high oil consumption.
Is the BMW 3 Series 318i reliable?+
Rather than a simple yes or no, it's best to weigh the proven pros and cons together. This page lists 5 verified findings.
How does Carbeak collect data?+
The cards on this page are derived from the Difetti fault database; compatibility of brand, fuel, engine, and generation between the source vehicle and target vehicle is verified. Topics with insufficient evidence are not shown.