* Water Pump: A failing water pump seal is a common cause. The weep hole (a small hole designed to alert you to a problem *before* major failure) might be leaking, or the seal itself might have completely failed, allowing coolant to pour out from around the pump.
* Intake Manifold Gasket(s): Leaks here are less common to result in a *flood*, but if the gasket(s) are severely damaged they could allow coolant to leak into the lower engine area and eventually drip out from the bottom.
* Cylinder Head Gasket(s): A blown head gasket is a serious problem. Coolant can leak into the oil, causing a milky substance, or it could leak externally, finding its way to the lower engine compartment. This would likely also cause other symptoms like overheating and white smoke from the exhaust.
* Freeze Plugs (Core Plugs): These are relatively inexpensive and are located in various places on the engine block. A corroded or damaged freeze plug can leak.
* Cracked Engine Block or Head: This is a catastrophic failure, likely accompanied by other significant symptoms.
Important Note: Simply seeing coolant on the ground isn't sufficient for diagnosis. You need to locate *where* the coolant is coming from on the engine itself. You should be cautious when doing this, as the engine will be hot for quite a while after operation. It is highly recommended to have a qualified mechanic diagnose and repair this issue to prevent further damage to your engine. Continuing to drive with a significant coolant leak can lead to overheating and potentially catastrophic engine failure.
