SA Lube's Magnatec 10W-40 A Up to 75% of engine wear happens while your engine warms up. When the engine stops oils drain off critical engine parts, however, Castrol MAGNATEC’s intelligent molecules don’t. They cling to the engine like a magnet providing an extra layer of protection. Castrol MAGNATEC’s unique formulation protects from the moment you start, dramatically reducing* engine wear. (4 x 5 Litres)