JHZR2
Staff member
Originally Posted By: d00df00d
Originally Posted By: ryan2022
I've always wondered this though.
I wonder if some manufacturers spec a 5w or 10w for a reason over the newer 0w oils. Maybe some engine designs need slightly higher viscosities for cold start up cusion.
Just a thought. It does make sense. Obviously the clearances in an engine will be different when cold, than when fully warmed up. If the internal parts have a higher rate of expansion and start out as a looser fit, I think you'd want the cusion............Maybe I had too many glasses of wine last night.
Again: GC 0w30 is THICKER at MOST TEMPERATURES than most 5w30s and some 10w30s. If what you are saying is true, everyone should spec GC.
When the difference between the hot viscosity number (20, 30, 40, etc.) and the winter rating (0w, 5w, 10w) is big, that usually indicates a higher viscosity index. A higher viscosity index usually means higher volatility and lower shear resistance, all else equal (although GC is extremely shear stable). If a 5w is all most people need for the winter, that is all the manufacturer will spec. No reason to stretch things more than necessary.
+1 d00df00d is correct.
Originally Posted By: ryan2022
I've always wondered this though.
I wonder if some manufacturers spec a 5w or 10w for a reason over the newer 0w oils. Maybe some engine designs need slightly higher viscosities for cold start up cusion.
Just a thought. It does make sense. Obviously the clearances in an engine will be different when cold, than when fully warmed up. If the internal parts have a higher rate of expansion and start out as a looser fit, I think you'd want the cusion............Maybe I had too many glasses of wine last night.
Again: GC 0w30 is THICKER at MOST TEMPERATURES than most 5w30s and some 10w30s. If what you are saying is true, everyone should spec GC.
When the difference between the hot viscosity number (20, 30, 40, etc.) and the winter rating (0w, 5w, 10w) is big, that usually indicates a higher viscosity index. A higher viscosity index usually means higher volatility and lower shear resistance, all else equal (although GC is extremely shear stable). If a 5w is all most people need for the winter, that is all the manufacturer will spec. No reason to stretch things more than necessary.
+1 d00df00d is correct.
