@tintin1, @saboor73 (all senior pakwheelers)
Can 10W30 OR 10W40 Mineral (Caltex Havoline Formula) oil be used in older engines (civic 88) where 20W50 is used in routine? 20W50 gives heavy feeling and vibrations in the steering at idling. Changed oil yesterday with Caltex Havoline 20W50, which was looking thick in appearance and heaviness in engine sound/idling. I have heard here on PW that SN Grade oil covers all previous older grades and can be used in place thereof.