The invention relates an cleaning apparatus, system and method for parts of the heating/cooling system of an vehicle. The invention effectively impedes odour and pollution originating from micro-organisms growing on the cooling and heating units. The cleaning assembly (220) according to the invention comprises of distribution tubes (225) provided with nozzles (230) arranged to spray cleaning substance onto the surfaces of the cooling and/or heating units (200, 232). The distribution tube preferably extends through at least a portion of the plurality of heating/cooling flanges (215) of the heating/cooling units and the nozzles are provided in the spaces formed between two adjacent flanges.