Quote:
Originally Posted by tanque55
Well after I posted this I did a search, should of done it before posting I know, but I am still a little confused. I was reading a post (actually a lecture on oil, oil 101, oil 102 ect....
Conclusion being that most engine wear occurs at start up and using the 0 and 5 -30 will protect the car as good as the higher 40s and 50s as most have the same protection at operating tempatures. The lower number supposedly flowing better at start up. I guess the old notion higher viscosity protects better is not always correct.
|
That is not necessarily correct as it totally leaves out several issues pertinent to start up (film strength, additive types, base polymer technology or oil “Group”, etc.). Realistically, the “W” or cold viscosity choice should factor in everything, including the ambient temperatures the car is going to see. That said, most OEM “recommended” W viscosities have more to do with their desired impact on CAFÉ mileage performance than protecting your engine. Hence, when just a few years ago the OEM’s would spec 10W-X oil for use in near arctic conditions, now they spec 0W-X oils for use in LA and Dallas, which obviously begs a question or two as to why they recommend such a thin oil.
On the higher temperature viscosity, the actual choice of weights is very germane as it directly impacts the level of protection the oil affords your engine under load conditions. Because these engines run much hotter than most owners know, XW-40 is the minimum level of viscosity you should be considering, with the “W” weight choice based upon the lowest temperatures the car is going to see. For all but the most extreme cold condition’s, a 5W-40 or 10W-40 oil would offer you the best trade off combinations. From there it would be the level of ZDDP, base polymer type, etc.