First this is the best write-up on motor oil I have ever read!
Quote:
Originally Posted by chicksdigemtoo  The best way to figure out what viscosity of oil you need is to drive the car in the conditions you will use. Then use the oil viscosity that gives you 10 PSI per 1,000 RPM under those circumstances...
These same rules apply to engines of any age, loose or tight. Just because your engine is old does not mean it needs a thicker oil. It will need a thicker oil only if it is overly worn, whether new or old. Yet the same principals of 10 PSI per 1,000 RPM still apply. In all cases you need to try different weight oils and see what happens. Then choose the correct viscosity. |
So given Dr. Haas's 10 PSI / 1000 RPM rule of thumb, I was off to see how my Tundra was performing on a fresh oil change with Mobil One 5W-30 Synthetic Blend.
I tested 1K, 2K and 3K RPM using the factory gauges.
As I suspected the results are not exactly linear . That said, does anyone know what the factory oil gauge actual PSI reference is. I checked the manual with no luck.
-wleeb