FIELD: transport engineering; fuel tanks of internal combustion engine-powered vehicles, such as automobiles. SUBSTANCE: in proposed method of diffusion protection of fuel tank manufactured of shockproof thermoplastic material inner surface of fuel tank is oxided or sulfonated prior to application of metal coating. Then surface is treated with reducing agent and water solution containing ions of metal for their reducing from water solution on tank surface. Treatment with water solution containing ions of metal is carried out until thickness of film on tank surface is 0.003 mm, minimum. EFFECT: improved quality of surface.
