^^ I have ran a late 80s Honda Accord engine for about a total of 400,000 kms or something and the oil used was Caltex Supreme and later on Havoline Motor oil API - SF, SG, SH. 20W50 viscosity changed out at 5000 kms on the dot with new oil filter of MANN, Union or VIC - whatever was left in my box of filters. Air filters were donaldson - and they lasted a year in that car before going bad in Karachi dust. That engine still was strong and troublefree after those years. Mind you it never ran plain water as coolant when under my maintenance and almost never had the A/C off.
Even my diesel engine had oil change at every 5000 kms along with its oil filter. Sometimes at 6000 if I travelled highway a lot. (Caltex Delo Silver 15W40 or the same grade shell, Mobil, Fuchs, ZIC, Emarat) - usually Caltex as I had a drum of it.
I always ran the engines at correct temperature - the Honda had a 82C thermostat in it and the VW had an 89C thermostat in it. The reason is that when oil gets hot water and condensate can flash off eliminating the chances of acid formation, corrossion, sludging etc. The cylinder heads were sparkly inside too.
IMO 3000 kms oil change is akin to wasting money.