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.
When a car heater doesn't work, the most common cause is low coolant. When troubleshooting to try and repair the car heater, check the coolant ONLY when the engine is cold. That's because removing the coolant cap on a hot pressurized system can result in severe burns.