Oil is an essential lubricant in your engine. It lets metal press against metal without damage. For example, it lubricates the pistons as they move up and down in the cylinders.
1 By the time of the Japanese surrender in August 1945, Korea was the second-most industrialized nation in Asia after Japan itself.  But the wartime mobilization of 1937-45 had reintroduced harsh measures to Japanese colonial rule, as Koreans were forced to work in Japanese factories and were sent as soldiers to the front.
Truman Takes the Steel Mills. On June 24, 1950, North Korea invaded South Korea. The United Nations Council called on all U.N. members to help repel the invasion. Under his authority as commander in chief of the armed forces, President Harry S. Truman ordered American troops to help defend the beleaguered South Koreans.