So after engine overhaul, mechanic set the Fan on auto, but he didnot put thermostat valve, i asked him but he was not in favor, second he put 20w-50 oil in car and asked me to never pour any other grade than 20w-50 in these old cars...i asked him that can i pour 10w-40 synthetic of shell, but he said NO, only 20w-50 mineral..
So my question is for all of you who kept suzuki khyber
1– Do i need to put thermostat valve in the first place? And if yes, then do i have to remove it in Summers??? Or It won’t heat up the car in summer??
2– which grade of oil shall i use after engine rebuild??? 20w-50 mineral, as the mechanic said or 10w-40 synthetic??