Mr. CATERHAM, I have a question. In a recent thread, I forget which one, you told a poster that 10w30 is an obsolete grade and he should use 5w- or 0w30 instead.
Here is my reasoning for using 10w30, and I'd like your comments on whether or not it makes any sense: in the PDF for Valvoline NextGen GB, it says that the NOACK of 10w30 is 11.3, and for 5w30 it's 14.4. That's an approximately 22% improvement in NOACK. Also, I ASSume that the 10w30 uses less VII than than the 5w30, which could lead to better viscosity retention, both kinematic and HTHS.
Also, I haven't started an engine in really low temps in over thirty years, and I don't see that changing real soon. Some winters here, we get a little frost in the mornings, so I'm sure that a 5w30 would pump a little faster, but most of the year it's going to be at least 50-60 deg at the coldest part of the day.
Here is my reasoning for using 10w30, and I'd like your comments on whether or not it makes any sense: in the PDF for Valvoline NextGen GB, it says that the NOACK of 10w30 is 11.3, and for 5w30 it's 14.4. That's an approximately 22% improvement in NOACK. Also, I ASSume that the 10w30 uses less VII than than the 5w30, which could lead to better viscosity retention, both kinematic and HTHS.
Also, I haven't started an engine in really low temps in over thirty years, and I don't see that changing real soon. Some winters here, we get a little frost in the mornings, so I'm sure that a 5w30 would pump a little faster, but most of the year it's going to be at least 50-60 deg at the coldest part of the day.