use 10W30 period, non sythetic for the first 5K miles. 10W40 should be discontinued. In a nutshell in order to get a multi-visosity
oil, fillers must be added to the base stock, the greater the range the more fillers, fillers do not lubricate but take up space, so a 10W40 has less "
oil" than 10W30 because of the additional fillers. 20W50 is way to heavy. Straigt 30 weight is to heavy, like i said 10w30 do not make a career out of it.