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Monday, 23 February 2015

What is the Shelf Life of Synthethic Motor Oil?

How do you extend the shelf life of synthetic motor oil?

Every now and again the debate around the shelf life of synthetic motor oil raises it’s head. In these debates it’s important to remember that motor oil retains its chemical properties if the oil is properly stored. Correct oil storage protects the oil, and consequently increases the engine oil shelf life over extended periods.

Synthetic oil does not contain contaminants like paraffinnic waxes, which are present in crude oil. Shelf life of synthetic motor oil basically depends upon the chemical compounds and additives being used and the storage environment.

The shelf life of synthetic motor oil is largely dependant on the additives.

The shelf life of synthetic motor oil is dependent upon the additives and the environmental conditions. The engine oil quality may deteriorate, and sludge may be formed, if moisture is introduced into the oil due to condensation or mishandling. Water reacts with the oil additives to produce insoluble substances that reduce the shelf life of synthetic motor oil. Moisture may also lead to microbial growth in the lubricants.

It is recommended that the storage temperature should be stable. Generally, temperatures below -10ºC or above 40ºC will cause oil degradation, with reduced lubrication capability. Extreme low temperatures may form sediments, and separation of additives. Manufacturers normally recommend a storage temperature between 5 degrees and 30 degrees Celsius.

The shelf life of synthetic motor oil can be extended if the oil can is not opened. Finally, the shelf life is also influenced by the product design. Elements like copper and iron can act as catalysts to promote the process of oxidation, and consequently reduce the shelf life.

Additives that Prolong the shelf life of synthetic motor oil.

Several additives are added to increase the shelf life of synthetic motor oil, produce stable oil that will maintain proper viscosity and will flow correctly at low temperatures, and meet other test parameters at a wide temperature range. They improve these characteristics:
A decrease in viscosity makes the oil unable to protect the engines from close metal contact, due to which wear is increased. Additives are used to improve the viscosity that is preserved for longer durations during the shelf life. This unit of viscosity is SUS, and its maximum recommended limit of deviation is plus or minus 15%. Viscosity determines the oil flow ability. It is the property to improve and preserve a particular quantity of sheering stress, and offer flow resistance. Thin oils have low viscosity while thick oils have high viscosity. This is a vital oil characteristic, since oil that has an extremely low viscosity may shear and cause the film strength to be reduced excessively at higher temperatures.

Oils with extremely high viscosity may not reach distant components at lower temperatures, or the oil film may be torn at high RPM.

  • Pour point depressants are used to decrease the freezing point of oils. 
  • Dispersants and detergents assist in keeping the oil clean and avoiding the formation of sludge. Contaminants are suspended in oil due to the use of dispersants. 
  • Oxidation inhibitors preserve the stability of oil. 
  • Rust and corrosion inhibitors are used for protection against condensation. 
  • Defoamants prevent foaming of the oil. 
  • Alkaline additives are used for the neutralization of acids. This characteristic is measured in Total Base Number (TBN). Oils with greater value of TBN will provide better acid neutralization. Most car motor oils are produced with TBN of 4 to 8. 
  • Calcium additives are added for protection from oxidative failure and also to prevent the development of varnish and sludge.

Storage Recommendations to extend the shelf life of synthetic motor oil.

The storage of synthetic engine oil and storage techniques can significantly affect the shelf life of synthetic motor oil. Generally, a dry and clean space with a stable and fair temperature, with suitable racks, will increase the shelf life. A dusty and humid atmosphere with irregular temperatures will seriously affect the estimated shelf life.

The manufacturers recommend the oil shelf life based upon the additives used for each type of their product. For example, oil lubricants that include rust inhibitors can lose their functional capabilities in a short time of storage. The oil stored should be rotated to ascertain that the recommended storage life is not inadvertently exceeded.

Most producers supply a suggested storage practice to increase the oil shelf life.

Temperature variation may move air in the environment causing thermal siphoning of the container. Movement of air is increased in a container that is not completely full and has more vacant space. Although the barrel is sealed properly and oil does not seep out, a firm container still draws in air with a drop in temperature, and blows it out with a rise in temperature.

Contaminants and moisture come into the oil, along with air that leads to degradation of additives and oil base. Water condensation may occur in the drum, with water layer being formed at the bottom that is pumped to the engine.

While extreme cold or hot temperatures can reduce the shelf life of synthetic motor oil, it’s important that only quality synthetic oils, such as those produced by Habot Oil, are used. If you’re unsure how to maximise the shelf life of synthetic motor oil, the professionals at Habot Oil will be able to advise on the best solution.