Nissan Repair: Xterra Heater Core, nissan xterra, head gasket

Question
I have a 2000 Nissan Xterra V6.  After a first diagnosis of a cracked head, we had a second opinion.  Was told it was a head gasket we had repairs done new water pump, etc. to the tune of $1800. Two weeks later the radiator went - $180.  Now they are telling us the heater core is bad - $480.  Should we keep putting money into this or is there an underlying problem?  P.S. We barely drive this vehicle as we were going to use it as 3rd vehicle for kids.

Answer
Sharon,

First, have them loop the heater hose and see if the problem of a leaky heater core goes away.  If it does then have the heater core replaced.  If a system over-pressurizes it will blow things like the radiator and heater core.  But, I would like to be sure the problem with overheating is gone.  A pressurized system will not overheat.  That is, if they loop the heater core hose back to the engine and take the heater core out of the loop and the vehicle runs normal then replace the heater core.  If the vehicle overheats then they need to let you know what else could be wrong.  If you are looking at an engine then you might sell the vehicle.  Just loop the heater core hose back to the engine first to make sure.