CITGO CITGARD SynDurance Synthetic Engine Oil SAE 5W-40 is ideal for engines operating in a wide temperature range, thereby avoiding the use of SAE 10W-30 in winter and changing to 15W-40 during summer months. It promotes fuel savings and exhibits excellent high-temperature wear protection. Not only does the product promote longer engine life, but it also provides drain interval optimization capability. Examples of such extreme service applications include emergency vehicles, vehicles with frequent cool down/restart cycles, refrigeration, generator sets, and standby engines.