Here are the most likely culprits:
* Lean air/fuel mixture: This is the most common cause. The engine is receiving too much air and not enough fuel, resulting in incomplete combustion. The unburnt fuel ignites in the exhaust system, causing the extreme heat. This could be due to a faulty oxygen sensor, mass airflow sensor (MAF), fuel injector, or a vacuum leak.
* Restricted exhaust system: A clogged catalytic converter, muffler, or exhaust pipe will back up exhaust gases, increasing pressure and temperature.
* Ignition problems: A misfire or faulty ignition system can also cause incomplete combustion and lead to higher exhaust temperatures.
* Cooling system issues: While less likely to directly cause a glowing manifold, a failing cooling system can lead to overheating of the engine, which could indirectly contribute to higher exhaust temperatures.
* Low compression: If one or more cylinders have low compression, incomplete combustion is more likely.
What to do immediately:
1. Turn off the engine immediately. Continuing to run the engine with a glowing exhaust manifold risks serious damage, potentially including melting parts of the exhaust system or causing a fire.
2. Let the engine cool completely. Do not attempt to diagnose or repair anything until the engine is cool to the touch.
3. Do not drive the vehicle. Have it towed to a qualified mechanic for diagnosis and repair.
Ignoring this problem could lead to catastrophic engine damage, requiring costly repairs or even a complete engine replacement. Get it checked out as soon as possible.
