Castrol EP 80W-90 is a mineral based extreme pressure multi-purpose oil containing anti-oxidant, anti-corrosion and anti-foam additives to protect against problems due to oil oxidation, gear tooth corrosion and oil foam. It also contains a special extreme pressure additive to cope with the condition of high rubbing pressures experienced in hypoid units. Recommended for the lubrication of spur and helical gears, such as used in automotive manual gearboxes, where the manufacturer specifies the use of an EP oil to API GL-4.