Why Is My Car Leaking Antifreeze?by MJ Knoblock
Cars are not supposed to leak antifreeze, also known as engine coolant. The fluid runs from different parts of the engine to others and is always contained. If you see this greenish fluid on the ground or other engine parts, something is broken or split and must be repaired or replaced.
By looking underneath the car, you can see the fluid and pinpoint the origin, the reason why it's leaking.
The radiator holds and circulates antifreeze. A hole or crack in this causes a leak or drip.
Hoses connected to the radiator can burst or crack due to wear, dry rot or puncture, causing visible leaks.
The head gasket is the seal between the cylinder head and engine block. If the oil dipstick is milky, there is probably antifreeze in the oil from a blown head gasket.
A bad freeze plug in the engine block may crack and cause a leak visible pool of engine coolant on the ground.
Three other sources include the thermostat, heater core and water pump, which can wear out and leak.