Change Car Glow Plugs BMW 4-Series
Change Car Glow Plugs
| Estimated time | 1h30–8h00 |
|---|---|
| Estimated labour cost | ~150–800£ |
| Difficulty | Intermediate |
| Vehicles |
4-Series 2013-2020 14
4-Series 2020-2025 1
|
What is the role of BMW 4-Series glow plugs?
Glow plugs are used in diesel engines to preheat the combustion chamber before starting, particularly in cold weather. Unlike petrol engines that use spark plugs to ignite the fuel, diesel engines rely on compression ignition. Modern glow plugs also remain active after starting to reduce emissions and noise during the warm-up phase.
When should you change your BMW 4-Series glow plugs?
Generally, glow plugs last between 80,000 and 160,000 km. Symptoms of failing glow plugs include: difficulty starting in cold weather, white or grey exhaust smoke on start-up, rough idle during warm-up, the glow plug warning light remaining illuminated, and increased fuel consumption.
How do I know if the BMW 4-Series glow plugs need changing?
Via the EOBD diagnostic system, faulty glow plugs will trigger fault codes (typically P0380–P0384 for glow plug circuit faults). Individual glow plug resistance can be measured with a multimeter (typically 0.5–2 ohms for a good plug).
Is it difficult to change BMW 4-Series glow plugs?
Difficulty level 3/5: intermediate. Glow plugs can seize in the cylinder head over time due to heat and corrosion, making removal difficult and risking breakage. Key steps: warm the engine first, apply penetrating oil, use the correct glow plug socket, unscrew carefully (do not force — a broken glow plug requires specialist extraction).
2 models covered
| Model | Year Range | Engines covered | Fuel |
|---|---|---|---|
| 4-Series 2013-2020 | 2013-2020 | 418d Diesel (B47D20A), 418d Diesel (N47D20C), 418i Petrol (B38B15A), 420d Diesel (B47D20A), 420d Diesel (N47D20C), 420d, -xDrive Diesel (B47D20A), 420d, -xDrive Diesel (N47D20C), 420d, -xDrive M Performance Diesel (B47D20A), 420d, -xDrive M Performance Diesel (N47D20C), 420i, -x… | Diesel, Petrol |
| 4-Series 2020-2025 | 2020-2025 | 420d mHev, -xDrive 48V (MHEV),Diesel (B47D20B+JA1), 420d mHev, -xDrive 48V (MHEV),Diesel (B47D20B+JA1), 420i Petrol (B48B16A), 420i, xDrive Petrol (B48B20A), 430d mHev, xDrive 48V (MHEV),Diesel (B57D30B+JA1), 430i, -xDrive Petrol (B48B20B), M4 Competition, -xDrive Petrol (S58B30… | 48V (MHEV), Diesel, Petrol |
