@Bird-man,
30W (SAE 30) oils are meant for cold climates and thus your manual might be right but just.Mechanics or experts will advise you upgrade your oil to 40W since we are in the tropics.The 40W is also recommended for drivers who are more often on the highway and have "bigger and faster machines".If you have a 1300cc town runner,30W still serves good enough.
Synthetic versus conventional motor oil?.Any person who tells you that synthetic is not for cars with 150K Km requires a kimanyoko.Synthetics have superior qualities and thus can last you upto 3 times conventional oil,their only con being the price depending
Nothing great was ever achieved without enthusiasm.