Auto parts prepared from polyurethane are manufactured by a process comprising:(a) preparing a polyol component by blending a stabilizer combination of (A) nickel dibutyldithio carbamate with (B) N-mono- or dimethylphenyl-N'-mono- or dimethylphenylphenylenediamine and/or (C) N,N'-diphenyl-p-phenylenediamine with a polyol and carbon black;(b) reacting said polyol component with a polyisocyanate: and(c) molding said reacted mass.