Oil in the water

Thanks for checkin in Rusty. New Rad. I've tried to skim the oil off the top of the water, been thru about 20 towels. BTW I'll fire the sob who left the towel in the wrong place, lol. It looks like a coating on the surface, I'll try to get a sample. Engine runs great, doesn't seem to have a dead cylinder.

I wouldn't sweat it just yet. Might be nothing to worry about. It's a new build too, right? Could be protective oil from the radiator as well as some left over cleaning chemicals from the machine shop in the block. Lets not condemn anything yet. lol