Buna-N Heat resistance Up to 100°C (212°F) with shorter life @ 121°C (250°F) Cold flexibility Depending on individual compound, between -34°C and -57°C (-30°F and -70°F) Chemical resistance Aliphatic hydrocarbons (propane, butane, petroleum oil, mineral oil and grease, diesel fuel, fuel oils) veg¬etable and mineral oils and greases HFA, HFB and HFC fluids Dilute acids, alkali and salt solutions at low temperatures Water (special compounds up to 100°C) (212°F) Not compatible with Fuels of high aromatic content (for flex fuels a special compound must be used) Aromatic hydrocarbons (benzene) Chlorinated hydrocarbons (trichlorethylene) Polar solvents (ketone, acetone, acetic acid, ethylene-ester) Strong acids Brake fluid with glycol base Ozone, weather and atmospheric aging