In the equation:

[Co(H2O)6]+2(aq) + 4Cl–(aq) + heat ⇌ [CoCl4]-2(aq) + 6H2O(l)

does increasing the volume within a system shift the equilibrium to the left of right?

why does this occur?

Adding H2O will shift the equilibrium to the left so that more of the hydrated complex on the left will form.