Take +/- 2" length of heat shrink tubing of the smallest diameter that will telescope over the cooling line, slip it about 3/16" over the line, and shrink it end to end. Feed the skinny end of the heat shrink through the hole, grab it, and pull the line through. The heat shrink will pull off the end of the cooling line as soon as it clears the hole, but will leave enough line exposed to grab. I don't know if this is anything new, but it works like a charm.