You guys seem to really like the multi-vis oils. The truth is that with 10w-30,10w-40,15w-40 and 20w-50 my truck rattles when I start it(392 I.H.C. v8). Doesn't rattle with Sae 30, holds good oil pressure and uses less oil. So whats wrong/bad with straight weights? I live in the desert so extreem cold is not an issue......I saw snow once....On tv It does get 120 degrees in the summer though.