Quote Originally Posted by Good Wrench View Post
Should I thin out the oil some more?
How tight are the clearances in the motor?

If it's a new build with modern tight clearances, I prefer 5-30 or 10-30. If it's a new build with older standard clearances, I prefer 10-30 or 10-40 and 15-50. If it's got some miles on it, I prefer 20-40 or 20-50.

With multi viscosity oils, the first weight# is the viscosity COLD, the second HOT. In other words in your case with 20-50, at cold start the oil viscosity is 20 weight and at it's higher operating temperatures no more than 50 weight. This can vary a little depending on the temperatures the manufacturer designed into the oil viscosities.