- Superior Load Carrying Ability - The EP additives contained in all Spirax HD oils provide excellent, long lasting protection against scuffing and minimize wear, even in the toughest operating conditions._x000d_ - Superior Thermal and Oxidation Stability - Spirax HD provides superior resistance to high temperature decomposition (breakdown). Even when operating conditions approach 150 °C, Spirax HD outperforms conventional API GL-5 lubricants. This improved thermal and oxidation stability helps ensure that deposits do not form around seals and helps maintain clean bearing surfaces to minimize wear._x000d_ - Potential for Fuel Economy - Spirax HD multigrade and low temperature range features lessen frictional energy loss which improves fuel economy.