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.