Abstract: The design and construction of past injector assemblies having an injector sleeve manufactured from a deformable material used the deforming characteristics of the injector sleeve to form a combustion seal separating a combustion chamber from a cooling liquid jacket. Additionally, the injector sleeve was generally used in conjunction with a resilient means to form the coolant seal between the cooling liquid jacket and a fuel injector. Deforming the injector sleeve to produce the combustion seal made it difficult to remove during inspections and maintenance schedules and virtually impossible to reuse. The present invention overcomes these problems by providing an injector sleeve manufactured from a relatively non-deformable material which is used in conjunction with a plurality of seal rings to establish only a coolant seal between the cooling liquid jacket and a fuel injector.