ModerateAffected: 2007-201270,000–130,000 miles

BMW 3 Series E90 320d N47 2.0d 177bhp — EGR Cooler and Valve Failure

EGR 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.

Severity

Moderate

DIY Difficulty

Hard

Est. Cost

£600–£1200

OBD Codes

P0401P0402P0128

Component Diagram

EGR

Typical layout and location for the EGR assembly.

Reference Illustration

Symptoms

Coolant loss without external leak
White smoke on startup
Rough idle and hesitation
P0401 EGR fault codes
Smell of coolant from engine bay

Root Cause

The EGR cooler corrodes internally. Combined with the EGR valve carbonising, this becomes a double failure. The coolant leak into the intake can cause misfires and carbon build-up in the valves.

How To Fix

Replace EGR cooler (BMW part or quality OEM equivalent)
Clean or replace EGR valve at same time
Flush intake manifold
Change coolant with BMW LL coolant specification
Total repair: £600-1,200 at specialist

Estimated Repair Costs

Repair Option	Est. Cost (GBP)
DIY (parts only)	£240–£480
Independent Garage	£600–£1200
Main Dealership	£960–£1920

Other Faults on This Variant

N47 Timing Chain Failure (Rear of Engine)

Critical

2007-201280,000–160,000 miles£2000–£3500

The 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

Critical

2007-201260,000–120,000 miles£30–£5000

The 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.

Excessive Oil Consumption / PCV Valve Failure

Moderate

2007-201270,000–140,000 miles£150–£400

The N47 engine can consume significant amounts of oil due to a blocked Positive Crankcase Ventilation (PCV) breather, forcing oil past the turbo seals or piston rings.

Disclaimer: Repair cost estimates are indicative and based on community data. Always get a quote from a qualified mechanic before proceeding with any repair.