Corrosion

Corrosion is often times associated with rust. In this case, corrosion refers to the acid formations that are a normal result of combustion. These corrosive substances, like sulfuric acid, accumulate in the oil and also on parts that the oil touches, such as valve stems and pistons.

Premium quality oil contains many additives, one of which is an acid neutralizer. This acid inhibitor fights the corrosion, but becomes less effective over time. This is because the inhibitor is consumed or evaporates from the oil. However, acid buildup in the oil can be reduced if the engine performs at operating temperature frequently. This causes the contaminants to be fully burned out of the hot oil (vaporized) and prevents them from condensing in the oil as harmful sludge. Contaminants should begin to vaporize at about 135° F. Most engines operate at around 180-195º F. (based on coolant temperature).

Cars that are not used frequently are prone to engine corrosion since moisture enters the engine through the air intake and exhaust systems. This is because moisture in the air condenses on cylinder walls at night. The moisture combines with fuel residue to form acid.

To minimize corrosion, it is important to have the engine reach operating temperature quickly so harmful acids are vaporized. Likewise, it is important not to operate the car in such a way that the engine never fully warms up, since the acids formed will not be completely burned.

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ENGINE WEAR
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ABRASION