10w40 or 15w50
, or 10w40 vs 15w50
. Wow, now two choices of my favorite subject, but I'm not sure if I can learn any more. Sure one of them is 6 yrs old and the other one is 4 1/2 yrs old but it is a topic that truely stands the test of time. One thing that is still not clear though, why exactly do the manufacturers and designers recommend certain wt oils? What makes them so smart? I hope those two thread go on and on. They are almost as good as that "sprocket" thread. Yours truely, rubber biscuit.