Let $\mathcal{C}_n =\left [χ_λ(μ)\right]_{λ, μ}$ be the character table for $S_n,$ where the indices $λ$ and $μ$ run over the $p(n)$ many integer partitions of $n.$ In this note we study $Z_{\ell}(n),$ the number of zero entries $χ_λ(μ)$ in $\mathcal{C}_n,$ where $λ$ is an $\ell$-core partition of $n.$ For every prime $\ell\geq 5,$ we prove an asymptotic formula of the form $$ Z_{\ell}(n)\sim α_{\ell}\cdot σ_{\ell}(n+δ_{\ell})p(n)\gg_{\ell} n^{\frac{\ell-5}{2}}e^{π\sqrt{2n/3}},$$ where $σ_{\ell}(n)$ is a twisted Legendre symbol divisor function, $δ_{\ell}:=(\ell^2-1)/24,$ and $1/α_{\ell}>0$ is a normalization of the Dirichlet $L$-value $L\left(\left(\frac{\cdot}{\ell}\right),\frac{\ell-1}{2}\right).$ For primes $\ell$ and $n>\ell^6/24,$ we show that $χ_λ(μ)=0$ whenever $λ$ and $μ$ are both $\ell$-cores. Furthermore, if $Z^*_{\ell}(n)$ is the number of zero entries indexed by two $\ell$-cores, then for $\ell\geq 5$ we obtain the asymptotic $$ Z^*_{\ell}(n)\sim α_{\ell}^2 \cdot σ_{\ell}( n+δ_{\ell})^2 \gg_{\ell} n^{\ell-3}. $$