Finding minimum and maximum of implicit functions

The equations of the system are

r1 = Sqrt[(x +μ)^2 + y^2 + z^2];r2 = Sqrt[(x - 1 +μ)^2 + y^2 + z^2];Ω = (1 - μ)/r1 +μ/r2 + 1/2*(x^2 + y^2) + (μ*(1 - μ))/2;Ωxz = Ω /. {y -> 0};μ = 0.0121506683;xL1 = 0.836914718893202;xL2 = 1.155682483478613;

And the contour plot of the implicit function is

C0 = 3.201;P1 = ContourPlot[2*Ωxz == C0, {x, xL1, xL2}, {z, 0, 0.2}, ContourShading -> False, ContourStyle -> {Black, Thick}, PlotPoints -> 50, PerformanceGoal -> "Speed"]

My question is how to find which value of $x$ corresponds to the maximum value of $z$ and what is the maximum value of $z$.

Similarly the minimum value of $z$ when $C0 = 3.012$.

My question is similar to this however the answers of this questions seem not working in my case.