Signs of a faulty car exhaust can include:
Loud and/or strange noises coming from the exhaust system. These can include grinding, rattling, or rumbling noises.
Decreased fuel efficiency as a result of reduced airflow.
Visible smoke or fumes emitted from the exhaust pipe when the engine is running. This can be white smoke, which indicates a coolant leak; blue smoke, which signals burning oil; or black smoke, indicating an overly rich fuel mixture.
Rusting on the underside of the car due to exhaust pipe leakage.
Vibrations and shaking from the exhaust system while driving.
If you notice any of these signs, it is important to consult a professional technicians right away.