Can you use the 0w30 in place of the 5w30? Winters coming on and it seems like 0w30 would provide better lubrication in cold weather?? or am I confused? Any downside to using the 0w30? This is for a 95 Toyota Landcruiser 4.5 liter 6 cylinder with 130K miles. It's been using synthetics for the past 100K miles.