hi there m8, im not sure what grade oil is in it....and as for the oil comsumption...it seems to be fine. i dont think theres any internal damage as it would smoke constantly.....my theory on the hill issue the other day would be, on vaccum its suckin real hard so its dragged some oil into the throttle body and burnt it off...once i opened the throttle it soon cleared up so i rekon the oils not been changed for a long time and or its the wrong grade and thin so its draggin through easier...would u recommend a thicker oil as the cars approx done 90,000 from what he told me coz its had the corra