Originally Posted by fishbone
........Why 40 instead of 30? Because it seems that per my last UOA the Mobil 1 5W30 still allowed some higher than average wear [had higher readings of iron, amongst others]
I think your fundamental problem is not that a 5W30 is inadequate, but that you have fuel and antifreeze in the oil. Solve the fuel and antifreeze contamination problem, and your wear will go down.