Abstract: A hose coupling assembly for use particularly in an automotive air conditioning system, or other system requiring the effective sealing of a refrigerant over extended periods of time, comprising a hose having an inner liner of thermoplastic material and being maintained in compression by a swaged sleeve over a fitting having a primary sealing element in the form of a resilient O-ring and a plurality of locking grooves into which the thermoplastic liner is to be cold-formed to preclude the possibility of the thermoplastic liner flowing during operation at elevated operating temperatures and to provide a secondary seal at all operating temperatures to which the coupling is exposed. The components, particularly the O-ring and fitting elements, being seized relative to one another to minimize flow of the inner liner at elevated operating temperatures and to maintain the O-ring as a live seal under all operating conditions.