Why Do Cars Rust?

One thing that scares car owners is rust. This pesky problem can make a car almost undriveable. However, you can keep your car from declining into a rusty junkheap. It requires monitoring and regular maintenance, but with some work, you could keep rust at bay. What causes rust in the first place? Here’s a technical explanation for the curious:

Rust is iron oxide, a molecule consisting of two iron atoms and three oxygen atoms. It's the product of an electrochemical process called corrosion. To create rust, three factors must be present: an anode, a cathode and an electrolyte. An anode is a piece of metal that will readily release electrons under the right circumstances. Cathodes are metals that will accept electrons. Electrolytes are liquids that facilitate the movement of electrons.

As electrons flow from the anode to the cathode via the electrolyte, the anode metal corrodes. In the case of metals with iron in them, part of the anode metal becomes rust. As the metal corrodes, it weakens. That's not something you want to have happen to your vehicle.

There are several points on your car that are more susceptible to rust. For example, your car's engine, frame, chassis, exhaust system and trunk compartment can develop rust. Optional equipment, like trailer hitches, can also fall prey to corrosion. Rust can even attack painted surfaces on your car.

Getting rid of rust is challenging. It's easier to take steps to prevent rust than it is to eradicate it. In the case of rust, an ounce of prevention is worth a pound of cure.

Read the full article (and get some great rust prevention tips!) here: http://auto.howstuffworks.com/under-the-hood/vehicle-maintenance/prevent-automotive-rust.htm