  We study Coulomb blockade (CB) oscillations in the thermodynamics of a
metallic grain which is connected to a lead by a tunneling contact with a large
conductance $g_0$ in a wide temperature range, $E_Cg_0^4 e^{-g_0/2}<T<E_C$,
where $E_C$ is the charging energy. Using the instanton analysis and the
renormalization group we obtain the temperature dependence of the amplitude of
CB oscillations which differs from the previously obtained results. Assuming
that at $T < E_Cg_0^4 e^{-g_0/2}$ the oscillation amplitude weakly depends on
temperature we estimate the magnitude of CB oscillations in the ground state
energy as $E_Cg_0^4 e^{-g_0/2}$.
