Oxypolymerized rape seed oil was tested for stability after addn. of corm 2,2'-thiodiethylene-bis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)] propionate antioxidant and/or after stripping with N(2) under 0.3 MPa. The peroxide no. and oxidn. induction time as well as tribolog. characteristics of the oil (seizure load) were detd. Use of the antioxidant resulted in the substantial improvement of the oil properties.