Is Cadillac have problem with the heater cores?

I searched online and found one instance of someone having to replace one. Parts fail all the time. Every vehicle has it's own issue or two, it's knowing what the issues are and being prepared for it. That is key.

GMs are more prone to electrical problems that can't be fixed than anything else. A heater core failure on a 6 year old vehicle is not uncommon for any make or model. But if it's not leaking and you had it diagnosed by someone other than the Dealer, get a second opinion. It could be a problem with the climate control system and I can guarantee you the shop has no idea of what they're looking at! Hope that helps! Jim