BMW 3 Series E90 320d N47 2.0d 177bhp — Wheel Bearing Wear and Drone
Wheel bearing wear is a normal consumable on UK roads, but frequent pothole strikes accelerate the failure rate significantly.
Severity
ModerateDIY Difficulty
Hard
Est. Cost
£120–£250
OBD Codes
None
Wheel Bearing
Typical layout and location for the Wheel Bearing assembly.
Symptoms
- Humming, droning, or roaring noise from the wheels that increases with road speed
- Noise changes pitch or disappears when turning slightly left or right
- Slight vibration felt through the steering wheel at motorway speeds
Root Cause
The sealed bearing unit loses its grease over time, or water ingress causes the steel balls/rollers to pit and rust. Impact damage from potholes can also cause a flat spot on the bearing race.
How To Fix
- Jack the car up and check for play by rocking the wheel at the 12 and 6 o'clock positions.
- Spin the wheel and listen for a rough rumbling sound.
- Press out the old bearing and press in a new OEM-quality bearing (e.g. SKF, FAG, SNR).
- Cost: £120-250 per corner
Estimated Repair Costs
| Repair Option | Est. Cost (GBP) |
|---|---|
| DIY (parts only) | £48–£100 |
| Independent Garage | £120–£250 |
| Main Dealership | £192–£400 |
Other Faults on This Variant
N47 Timing Chain Failure (Rear of Engine)
CriticalThe BMW N47 diesel engine has a timing chain positioned at the REAR of the engine, against the bulkhead. Chain failure is catastrophic, and repair requires engine removal. This is the most significant known fault in the BMW 3 Series range.
Swirl Flap Failure and Engine Ingestion
CriticalThe N47 intake manifold has metal swirl flaps on actuator rods. When the rods corrode and snap, the flap breaks off and gets ingested into the engine, causing severe internal damage.
EGR Cooler and Valve Failure
ModerateEGR cooler failure on the N47 is common from 70,000 miles. Coolant leaks into the intake manifold and the EGR valve sticks, causing power loss and rough running.
Disclaimer: Repair cost estimates are indicative and based on community data. Always get a quote from a qualified mechanic before proceeding with any repair.