I plan to replace the radiator, expansion tank, water pump, thermostat and housing as well as the major hoses.  How much farther into the system should I go?  What is the failure rate of the plastic water pipes under the intake manifold?  Seems like a lot of labor if they virtually never fail.  Same goes for the hoses to the heater core, although they are easier to get at.

Any feedback would be much appreciated.

Mark Chambers