Its time to get my oil changed, so im wondering which one to buy, what do you think about 5w50 for my DOHC ZC (d16a9) ? Or better 10-40 ? Car is mostly driven in high revs...
Depends, oil has different viscosity at different temperatures; i.e. if it's cold it's thick and if it's warm is thin. So what temperature is your oil operating at?but is it true that also a thin oil can make a bearing fail ?
Thin oil lubricates sooner because it moves faster. A SBC with a bunch of miles on it will have sufficient clearance for thick oil to move thru it pretty quickly, an import with its tighter tolerances may never have enough clearance to run thick oil. Most wear occurs at start up because there is not enough oil flowing to make a cushion of oil to reduce friction. The tighter the tolerance and the thicker the oil the longer it takes to build up this cushion.
Stay with the 10W30