Nissan Repair: xterra overheating, head gaskets, radiator cap

Question
I have a 2000 xterra with a 3.3 that started overheating on me. I fist changed the thermostat, then the water pump, and the head gaskets. I even replaced the radiator cap and flushed all the lines out. I was told that the timing might be wrong and the only other option i could think of was a new motor. Just wondering if you might have any ideals?

Answer
Everette,

If you have replaced all of these items I would do a test to see if there is exhaust gas in the radiator.  The parts store sells a kit that uses a fluid that changes color if exhaust is present.  If that is the case and you have replaced the head gaskets then a wrecking yard engine or a rebuild would be your best option since there is a crack somewhere in the engine or heads.  It all depends on how much time and money you want to spend to find the problem with this engine.  Also, if there is no exhaust present take the radiator out and make sure it is not plugged up and that the fans are working properly.