Hartex oils are based on a highly refined petroleum base oil and a set of additives that provide increased oil cooling rates and prevent the formation of varnish and deposits on hardened cast iron and steel surfaces. Hartex 70 oils exhibit very high durability and parameter stability over long periods of time while maintaining adequate heat load. Experience has shown that this oil can operate for up to 10 years in systems where proper cooling is maintained and the charge size does not exceed the optimum size. Recommended oil bath temperatures: - 40-80°C.