If you dispense your beer with a party pump, which uses air instead of CO2 to drive the beer, you can only expect your beer to remain fresh for 8-12 hours. If you keep your kegs warm, and drive them with CO2 through a jockey box or other faucet, they will most likely last a couple of months.
Rust by definition is the result of the oxidation of metal. One engine manufacturer refers to the process of corrosion in aircraft engines as galvanic corrosion which is a type of corrosion caused by dissimilar metals being in close proximity of each other. In this process an electrolyte such as water also needs to be present. Almost all metals will oxidize or corrode.
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.