Lubricating oils have an end date. Their usage is finite. The same applies to lubricating oil additives. They are not active or proactive forever. They are used up – consumed in the operation process or depleted.
How Depletion Occurs
Base oil additives are consumed. They are depleted in a variety of ways. The most common methods include:
- Adsorption: This is the adherence of additive molecules, ions, etc., onto metal and water surfaces
- Filtration: This produces separation
- Settling: This also results in oil/additive separation
- Decomposition: The oil additives breakdown/decompose
The result – the function of the lubricating oil additives is weakened. The package can no longer perform its functions as effectively as it had previously. This process continues until the entire package of oil and additives is not only completely ineffective but also presents a danger to the functions of the engine and its components. Any of the following may occur:
- Viscosity increases
- sludge formation begins
- Bearings and any metal surfaces are under attack from corrosive acids
- Wear of the bearings and engine metal parts begins to increase.
Additive depletion often serves as a tool for estimating the useful service life of base oil. Such an analysis not only helps assess whether the base oil is healthy but also provides indications of the causal factors of additive depletion. Since all lubricating oil additives break down over time, the longer an additive is in use, the more it will become depleted – lost during its lifespan to separation, decomposition and depletion.