MISREAD - basically this applies to ca20e, - if you have a leak AND coolant (or oil)gets onto the RUBBER timing belt - it is BAD for the belt, and may lead to PREMATURE FAILURE, ie. belt BREAKS. and all the associated problems.
any OHC car will not run if timing belt or chain is broken, with nissans interference engines you also get valve/piston damage - ie they hit.
a water pump leaks coolant because its gasket OR bearing is going,gone.
plus there are those pita hoses under the manifold that could be the cause of the leak. or any other part of the coolant system in the area. (eg in ca20 radiator top hose, thermostat housing, intake manifold etc). unfortunaltely around this age all these hoses/connectors start failing!