Abstract: A coolant line for air-conditioning systems that are operated with carbon dioxide as a coolant, particularly air-conditioning systems of motor vehicles, can be tightly connected at both ends to connecting parts. The line has an inside, metallic, corrugated hose that is coolant-tight, a radially pressure-resistant, flexible, metallic jacket that surrounds the hose with radial spacing and provides axial support, and a compression-proof, temperature-resistant intermediate plastic layer that fills the space between at least the radially-outside corrugation crests of the metal hose and the jacket so as to prevent play.