Exhaust & emissions

Rear exhaust silencer

Reduces exhaust noise before gas leaves the tailpipe.

Where it sits

Near the rear of the underbody.

How it works

Chambers, perforated tubes and absorbent materials shape sound; some designs include controlled flaps.

Think of it as

An acoustic maze that softens pressure pulses.

Symptoms when it fails

Rattles, corrosion or louder exhaust can involve mounts, shells or internal damage.

Lifespan

Condition, contamination, operating pattern and the underlying engine matter more than a universal age limit.

Repair cost

Sensors and joints differ greatly from complete after-treatment assemblies. First repair the cause of contamination or abnormal combustion.

The BMW angle

BMW M and standard exhaust designs may use different silencers and controls despite similar visible tips.

Used in

BMW combustion models; petrol and diesel after-treatment components differ by engine and market.

Sources
Same system

Exhaust & emissions