Here's why and what you should do:
* Catalytic Converters Don't Leak: They're sealed units designed to handle exhaust gases. A leak would indicate a catastrophic failure, likely involving a much larger problem than just a fluid leak.
* Engine Oil is the Most Likely Culprit: Black, oily liquid is almost always engine oil. The oil could be leaking from several places *near* the catalytic converter and dripping down onto it, making it appear to be leaking from the converter itself. Possible sources include:
* Valve Cover Gasket: A common leak point that can drip down onto the exhaust manifold and eventually the catalytic converter.
* Rear Main Seal (Engine): A seal at the back of the engine, near the transmission, which can leak oil onto the exhaust system.
* Oil Pan Gasket: A leak from the oil pan will eventually find its way down the underside of the engine.
What you should do immediately:
1. Stop driving the vehicle. Continuing to drive with an oil leak can cause serious engine damage.
2. Inspect the undercarriage carefully: Look for the source of the leak. Trace the path of the oil to find where it's originating. A flashlight and maybe even some shop rags to soak up some of the oil will help you pinpoint the leak.
3. Check your engine oil level: This will confirm whether you are indeed losing oil.
4. Take your vehicle to a qualified mechanic: This is crucial. They can properly diagnose the source of the leak and perform the necessary repairs. Ignoring the leak will only lead to more damage and costly repairs.
Don't try to fix this yourself unless you have significant mechanical experience. An oil leak is a serious issue that requires professional attention.
