I don't want to run this thread into the ground but maybe this will help us all. I brought this subject up with an 81 year old mechanic (my uncle) he said back in the thrities in Montana where he lived there was two types of oil that the farmers knew it was either light oil or heavy oil (no weights in them days). They would come in with a bucket and ask for light oil my uncle would go to the pump place the bucket under the spigget and spin the handle with one hand with no effort to pump the oil from the barrel. Next guy would come in and ask for heavy oil same barrel same spiggot and my uncle would spin the pump handle with both hands real slow and give a few grunts and the farmer would say that heavy oil is sure stiff but it works well in my tractor. My uncle says its all in their heads not in the oil. If they think it works it does.....Good enough I say. T/C Steve