* Exhaust Leaks: The most immediate consequence is an exhaust leak. This allows exhaust gases to escape before they reach the catalytic converter and muffler. This can lead to:
* Reduced Engine Power: The back pressure in the exhaust system is disrupted, impacting the engine's ability to efficiently expel exhaust gases and draw in fresh air.
* Rough Idle and Poor Performance: The engine may run rough, hesitate, or lack power, especially at higher RPMs.
* Increased Emissions: Unburned fuel and other pollutants escape into the atmosphere, potentially leading to a failed emissions test.
* Loud Exhaust Noise: You'll likely hear a noticeable exhaust leak sound.
* Damage to Catalytic Converter: The raw, unburnt fuel and higher temperatures from the exhaust leak can damage the catalytic converter, which is an expensive component to replace.
* Engine Heat Issues: A significant crack might allow excessive heat to escape, which *could* affect engine performance in some cases. This is less common than other issues.
* Oxygen Sensor Issues: Exhaust leaks can disrupt the readings of the oxygen sensor, affecting the engine's fuel mixture and potentially causing further damage.
In summary: A cracked exhaust manifold won't instantly destroy your engine, but the resulting problems are serious and will worsen over time. The longer you wait to repair it, the greater the risk of causing extensive and costly damage to other parts of your exhaust system and potentially even the engine itself. Repairing the manifold or replacing it is highly recommended as soon as you suspect a problem.
