How corrosion occurs?

Answer 1

Corrosion in a vehicle's electrical system can occur for several different reasons. Moisture on electrical contacts can cause copper to rust. This rust is blueish green and has an increased resistance to electricity causing a closed circuit. The solution is to clean the connections and apply electrical contact grease. It's also a good idea to make sure that any protective contact covers ( rubber or plastic ) are in good condition. Another type of corrosion occurs where high voltage spark is arcing across connections. This is true between the rotor and the contacts on the inside of the cap and on spark plug tips. Examination of these places on old parts will reveal that some of the metal is actually missing; the spark having caused particles of metal to fall off. This occurs slowly over long periods of use. The solution to this type of corrosion is to replace the parts. This happens to a lesser extent with normal voltage ( usually 12v ) on other electrical plugs, harness connections, fuses and relays. Cleaning these plugs is usually sufficient to get them operating properly. Another type of corrosion due to electricity in cars is caused by poorly grounded starter motors and is noticeable at coolant ports on vehicles with aluminum heads. When the ground strap between the motor is not clean the electricity from the ground of the starter motor produces ions in the coolant and can carry bits of aluminum away. When taking off the thermostat housing, for example, there will be rough spots where the aluminum should be smooth and some of the material will be missing. The solution to this problem is to clean the ground straps between the motor and the chasis. One can also add a ground from the starter bolt or starter body that runs directly to ground on the chasis.