We know mixing M1 is fine, due to the similar chemistry. But how does this work on a molecular level? Patman had a good point here:
quote:[ August 30, 2003, 07:02 PM: Message edited by: buster ]
One thing that has me curious is that if you mix two oils, how does it affect the HTHS? I wonder if it becomes an average of the two, or if it leans more towards the lower side? For instance, if you mix in Mobil 1 5w30 (with it's 3.08 HTHS) and Mobil 1 15w50 (with it's 5.11 HTHS), in an exact 50/50 ratio, will the resulting HTHS number then become 4.1? We know the viscosities might not behave exactly like this, due to different levels of VII in each oil, however the resulting viscosity should be pretty close to 91cst at 40c, and 13.7 cst at 100c, give or take a few %. So in effect you'd have something close to a 10w40 to 15w40 oil probably.