I have a 1984 Land Cruiser FJ60 with 196,000 miles. It runs great, uses about 1 quart of oil every 2500 miles. I change oil every 2500 miles, which for me is 4 times per year. During most of the year I run Delo 15w-40, but during the 3 hot months of the summer I switch to Chevron 20w-50...