The samples of (Mn$_{1-x}$Co$_x$)Si with $x=0.15$ and $x=0.17$ were grown their physical properties: magnetization magnetic susceptibility, resistivity heat capacity studied. data analysis included also the previous results at $x=0.057, 0.063, 0.09$. indicated doping MnSi Co completely destroys helical phase transition whereas basically saves fluctuation area normally situated slightly above te...