Lubricants in general are largely responsible for prolonging a machine’s life by reducing friction between components. While machines eventually wear out, enveloping components in lubricant delays the inevitable. For a lubricant to perform its job, it must exhibit specific properties while working under harsh conditions.
Arguably the most important of these properties are high boiling and low freezing points. Their values depend on composition and nature of their use, but lubricants must be able to maintain its viscosity under extreme heat and cold. The mediocre lubricant will evaporate when it boils until nothing is left; if it freezes, it will become too hard to do its job.
A petroleum product’s boiling point is relative to the number of carbon atoms present. Lubricants for vehicles generally have 18 to 25 hydrocarbon atoms and have a boiling point between 300 and 400 degrees. The normal temperature in a car engine must be from 195 to 220 degrees, so lubricants are more than enough for the job.
Similarly, the number of carbon atoms present is relative to the freezing point. Most lubricants in the market can maintain fluidity up to 20 degrees below zero, particularly those for car engines. However, these figures are average at best. Some lubricants have higher boiling and lower freezing points, designed for more heavy-duty applications.