Change Car Rear Silencer BMW 4-Series
Change Car Rear Silencer
| Estimated time | 0h45–2h30 |
|---|---|
| Estimated labour cost | ~75–250£ |
| Difficulty | Easy |
| Remove/refit the silencer | 0h45–2h30 |
| Renew the silencer | 0h45–2h30 |
| Repair the silencer* | 1h30 |
| Repair the front silencer* | 1h30 |
| Align the front silencer* | 0h30 |
| Repair the main silencer | 0h30 |
| Align the main silencer* | 0h30 |
| Difficult main silencer removal* | 0h30 |
| Remove/refit the rear silencer | 0h45–2h00 |
| Renew the rear silencer | 0h45–2h00 |
| Repair the rear silencer | 0h30 |
| Weld a sheet-metal repair panel onto the rear silencer* | 0h45 |
| Difficult rear silencer removal* | 0h30 |
| Remove/refit the main silencer | 1h30 |
| Renew the main silencer | 1h30 |
| Repair the main silencer* | 1h30 |
| Repair the rear silencer* | 1h30 |
| Remove/refit the front silencer | 1h30 |
| Renew the front silencer | 1h30 |
| Remove/refit the rear silencer trim | 0h30 |
| Renew the rear silencer trim | 0h30 |
| Remove/refit both rear silencer trims | 0h30 |
| Renew both rear silencer trims | 0h30 |
What is a BMW 4-Series rear silencer?
The rear silencer (also called the back box or rear muffler) reduces exhaust noise to an acceptable level. It is located at the end of the exhaust line, after the catalytic converter, particulate filter (if fitted), and sometimes an intermediate silencer.
When should you change the BMW 4-Series rear silencer?
No periodic replacement interval is specified. Carry out regular visual inspections for corrosion, holes, and deteriorated mounting rubbers. Signs that replacement is needed: louder exhaust noise, rattling from loose baffles, visible rust holes, exhaust fumes entering the cabin, or failure at the MOT/roadworthiness test.
Is it difficult to change the BMW 4-Series rear silencer?
Difficulty level 2/5: technically easy but may require effort if bolts and clamps are rusted. Key steps: raise the vehicle, apply penetrating oil to clamp bolts, remove the clamp connecting the silencer to the intermediate pipe, remove the mounting rubber hangers, fit the new silencer with new gasket/clamp, reattach mounting rubbers, check for leaks with engine running.
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 |
