I appreciate the responses, but there is no hose anywhere that is not hooked up. I used your link, Neil, and started searches of other sites, and seems that everything enlarged goes blurry. But there were a couple pics that appear to have cap of some sort on it. Gonna keep looking.

Greetings all, my 1st time here. New-ish car, 1st Volvo. This may be silly folks, but at the top of my radiator there is a hole, manufactured there, on the side of coolant filler. I see no hoses, no plugs, and I am totally freaked out by this. Sitting still the fluid stays in, but you open the fill ...