Are synthetic engine oils better than conventional oil at different operating temperatures?
Synthetic oils are primarily made from base oils that are more highly refined, producing an oil with fewer impurities, lower volatility, and increased temperature performance or Viscosity Index (VI). Viscosity Index is a measure of an oil’s change in viscosity resulting in changes in temperature. Oils thicken at low temperatures and thin at high temperatures. Synthetic oils are made with base oils that have a higher VI, meaning that they are more temperature stable with less dramatic viscosity changes with temperature.
This results in an oil that has improved performance at both ends of the operating temperature range. The improved cold temperature and volatility performance allow for oils to be blended at lower viscosities, such as 5W-30, as well as oils suitable for a wider range of temperatures, such as 0W-40. Shell Rotella T5 10W-30 or Shell Rotella T6 5W-40 are an excellent choice for operators of vehicle fleets in locations with large ambient temperature ranges - one oil to protect, whatever the season and is the viscosity grade recommended for use by most OEMs. Both oils have better low-temperature pumpability compared to conventional oil.
Do synthetic oils provide better oxidation control than conventional engine oils?
Synthetic engine oils offer better oxidation stability than conventional engine oils, which can lead to a longer oil life. Oxidation is driven by high temperatures which make severe operating conditions an excellent application for synthetic oils. Applications that have extreme operating temperatures, and/or where a maximum oil drain interval is desired are areas that need the improved performance of a synthetic oil.
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