Passing an expression to the Plot Function does not Work

Solving a differential equation I found that its solution was analytic, and I stored it as an expression from the default rule output of the DSolve[] function:

soleq2 = y[x] /. soleq2[[1, 1]]

Which has output:

Sqrt[x] BesselJ[Sqrt[13]/2, x] C[1] + Sqrt[x] BesselY[Sqrt[13]/2, x] C[2]

I then plotted this:

Manipulate[Plot[soleq2, {x, 0, 10}], {C[1], 0, 10}, {C[2], 0, 10}]

but the plot does not show anything, only the sliders for the modulation of C[1] and C[2]. I tried substituting these constants with other letters thinking their format might interfere with the kernel, but to no avail.