Hi YA from oz, I just changed my oil today and used as recommended an 15-40 thinner than the cheap stuff. Older cars use 20-50 thicker oil. The recommended oil is a bit more expensive but for the overhead cams etc it is better wear protection. The brand I used was Valvolene Engine Armour 15-40. I was using standard 20-50 shell helix standard and ticking during first startup was evident. Price was on special 6L for AU$18.95