"Is the 4 Serisi 425d reliable, and what should you check?"
The most frequently mentioned issue when buying a used BMW 4 Series 425d 2014 (F32 / F33 / F36 / F82 / F83): Oil cooler / oil cooling component failures. Also, EGR / swirl valve clogging (carbon buildup in intake ports) is commonly reported.
Engine: N47
N47D20D · 425d · Used in this car from 2014-2015
Strengths
Wide selection of versions and modifications
Economical for such power output
Watch-outs
Many problems with early diesel versions
Frequent oil leaks
Many versions have piezo injectors
Known engine issues
Timing chain driveEarly engines had low timing chain lifespan: guides wore out, chains stretched, and sharp teeth on the crankshaft sprocket accelerated the process. On updated N47TU or N47N engines, most weak points were eliminated.
Cracks in the blockThe aluminum block was initially designed without a special safety margin, and severe overheating could cause cracks between the second and third cylinders. With the update, the block was reinforced and such problems almost ceased.
Fuel systemAll engines in this series are equipped with a reliable Bosch Common Rail fuel system, but powerful versions with piezo injectors are quite demanding on fuel quality. Also, avoid driving with an empty tank, as the high-pressure pump may suck in air and start producing metal shavings.
Listed from most frequently reported, each with its source.
Oil cooler / oil cooling component failures
Often reported
Owners report breakage or leakage of the oil cooler and oil cooling circuit components; this can render the vehicle undriveable and cause difficulty in finding replacement parts.
Cooling
EGR / swirl valve clogging (carbon buildup in intake ports)
Often reported
Carbon buildup is reported in EGR valves and swirl flaps of modern N47 diesel engines; this can cause idle fluctuation and performance loss, requiring cleaning or disassembly.
Engine Bay
Worn timing chain
Often reported
In N47 engines (including 2.0 218 HP), the timing chain and guides frequently stretch and wear; this can cause rattling noises from the engine, electronic warnings, or loss of synchronization. Repair is labor-intensive.
Timing chain
DPF clogging or issues
Often reported
Diesel particulate filter (DPF) and regeneration cycles can cause problems, especially with city or short-distance driving; incomplete regenerations, warning lights, and need for cleaning or replacement may occur.
Exhaust Emissions
Turbo/actuator failures (VGT/wastegate)
Often reported
User reports and technical reports indicate failure or malfunction of turbocharger components (wastegate actuator or variable geometry) in BMW 2.0 liter diesel engines.
Turbo
BMW 4 Serisi 425d technical specs
BMW 4 Serisi 425d (2014): boot 445 L; fuel use 5,1 l/100 km (urban 6,3 l/100 km · extra-urban 4,4 l/100 km); 0–100 in 6.7 s.
Boot capacity
445 L
Fuel consumption
5,1 l/100 km (urban 6,3 l/100 km · extra-urban 4,4 l/100 km)
What should I look for when buying a BMW 4 Series 425d?+
When buying a 2014 425d, check the service history, test drive, and look for engine/transmission warnings. The most commonly reported issues: oil cooler / oil cooling component failures; EGR / swirl valve clogging (carbon buildup in intake ports); worn timing chain.
What are the chronic problems of the BMW 4 Series 425d?+
The most commonly reported issues: oil cooler / oil cooling component failures; EGR / swirl valve clogging (carbon buildup in intake ports); worn timing chain.
Is the BMW 4 Series 425d reliable?+
Instead of a simple yes/no, it's necessary to evaluate 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 Difetti fault database records; the source vehicle and target vehicle are verified for brand, fuel, engine, and generation compatibility. Topics with insufficient evidence are not shown.