Heater Cores?

[Spicekitty2000]

I own a Chevy S-10 4 x 4. (Original owner) Last March my heater core blew. Took it to the local chevy dealer. He replaced it. But today makes 6th trip back, since then, to service department to have it replaced. Service department manager has assured me that they have checked out everything, (including electrolosis, and blown head gasket) but the damn thing keeps blowing. Last trip was on 2-6 this year. They are convinced it is a bad batch of heater cores. Any suggestions or ideas? I am not inclined to replace it myself, but am tired of the inconvenience this is causing. (I also hate to freeze my butt off when I bypass it, in order to drive it to the dealer) Thanks for any ideas you might throw my way.