Losing Coolant but No Visible Leaks … Fixed! - 2007 Chevy Express 1500 4.3 L

Since I purchased this 2007 Chevy Van a couple of years ago I kept smelling coolant every time I got out after reaching my destination. I kept looking but could not find a leak, there was no dripping, it wasn’t seeping from the water pump, the exhaust did not smell like burnt coolant, and the oil was not contaminated with coolant. So at least there did not appear to be an internal leak such as a head gasket. I finally decided to pressure test the cooling system. So I got out and attached my Mitty - Vac pressure tester to the overflow tube of the plastic fill reservoir and began pumping air into the system. I could hear gurgling but couldn’t see any leak. I pumped and pumped but was only able to get 5-6 lbs of pressure that would leak down very quickly. I decided to remove the plastic shroud covering the radiator and kept pumping air into the system. I finally heard air coming out of the radiator and a slight mist of coolant developed coming from a pinhole in the upper back side of the radiator. It was happening since I purchased the van and would only leak when hot. It was so slight that it would evaporate immediately but left a strong sweet smell when stepping out in front of the van. The air pressure from the Mitty Vac exposed the problem. Unfortunately I didn’t get that part on video.