Dodge Repair: 2003 Ram 1500 multiple heater core failures, heater cores, heater core

Question
Hi.
I own a 2003 Ram 1500 Quadcab 4WD w/ the 4.7L engine.  I am now on my 4th heater core (installed Monday 11/17).  First one was replaced Feb/2007.  Second July/2008.  Third Nov/2008.  What is going on with these heater cores that fail so often?  The last one was a dealer part.  The replacement cores are $150, but labor is killing me at $500 a pop.  Anything I can do to get a beefier heater core?  It's obvious the ones I've had had either defects something else is going on.  Any ideas?
Thanks!
L

Answer
if u just put a mopar heater core in its under warranty and the dealer should take care of the part replacement for u  contact local dealer for the issue. The only other thing I can offer is some one does not know how to put them in   I do this sorta work and I have never had to put another one in once I installed it.