BMW 3 Series E90 320d N47 2.0d 177bhp — Glow Plug Failure / Snapping in Head
Diesel glow plugs burn out over time causing cold starting issues. The major problem is they often snap in the cylinder head when mechanics try to remove them.
Severity
ModerateDIY Difficulty
Moderate
Est. Cost
£100–£300
OBD Codes
P0380Injectors
Typical layout and location for the Injectors assembly.
Symptoms
- Hard starting in cold weather (below 5°C)
- White smoke on cold start for 30 seconds
- Flashing coil light or EML on dash
Root Cause
Carbon buildup around the tip of the glow plug effectively welds it into the cylinder head. Applying too much torque to remove it shears the threaded top off.
How To Fix
- Soak the glow plugs in penetrating oil for several days before attempting removal.
- Only attempt removal with the engine piping hot.
- If a plug snaps, specialist removal tools are required (£150-300 call-out fee).
- Standard replacement cost: £100-200
Estimated Repair Costs
| Repair Option | Est. Cost (GBP) |
|---|---|
| DIY (parts only) | £40–£120 |
| Independent Garage | £100–£300 |
| Main Dealership | £160–£480 |
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.