The application of polymer optical fibers (POF) in automobiles for data transmission is interesting because of their well known positive aspects. The environment in automobiles can be detrimental to POF. The influence of typical automotive fluids to the transmission behavior of different types of POF's has not been previously comparatively tested. A specific qualification test was designed and performed. The tested POF's differ in the jacket material. The test fluids were typical automotive fluids like fuel ( Diesel, Gasoline, Jet), oil (transmission, motor), brake fluid and carburater cleaner. The possible impact of the fluids to the POF was increased by raising fluid temperatures recording to a fixed profile. The transmission properties of the POF and the fluid temperature was continuously monitored for a maximum duration of 800 hrs..The chemical resistance of different jacket materials to the transmission behavior is shown. The difficulties of using POF under the influence of typical automotive fluids are discussed and some possible modifications suggested.