Castrol MAGNATEC STOP-START 5W-30 A3/B4 is suitable for use in automotive gasoline and diesel engines where the manufacturer recommends an ACEA A3/B3, A3/B4, API SL/CF or earlier specification 5W-30 lubricant. Castrol MAGNATEC STOP-START 5W-30 A3/B4 is approved for use in vehicles by leading manufacturers please refer to your owners handbook and the specifications section. Today even a normal driver can stop and start as many as 18,000 times a year. And all that idling in traffic or waiting at junctions causes microscopic wear in your engine. In the latest industry test, New Castrol MAGNATEC STOP-START 5W-30 A3/B4 gives significantly less wear in STOPSTART operation. New Castrol MAGNATEC STOP-START 5W-30 A3/B4 has intelligent molecules that cling, and form a self-healing layer so its always ready to protect at each of the critical stages of stop-start driving. Castrol MAGNATEC STOP-START 5W-30 A3/B4.