> Why not just undo the rubber hoses from both ends of both pipes and run
> garden hose water through from each direction. That should clear them or
> at least tell you where the blockage is. Be careful not to use too much
> pressure. The cooling system runs at under 20 psi and home water lines
> can be 100 psi.
>

I think that most city water systems run about 40 psi.

If your pipes won't handle that, you need to replace them anyway.

Larry A.