Twelve greases were prepd. by thickening mineral or synthetic oils with polyurea and improved by addn. of multifunctional additives and corrosion inhibitors and homogenization at 95-100 degrees C for 30 min and then studied for operational and lubricating properties and thermal stability by std. methods. The polyurea grease based on a synthetic polyalphaolefinic hydrocarbon oil showed high thermooxidizing stability and very good rheol. properties at low temps. Zn alkylaryldithiophosphate inhibited efficiently the oxidation processes in presence of O-2. Ca dinonylnaphthalene sulfonate showed good corrosion protection power. Zn dialkyldithiophosphate was also very efficient also polyfunctional additive.