I just left the dealer after replacing the radiator and the water pump. As I'm driving home, I discover that the heater is blowing cold air. Is this a coincidence or is it possible the dealer did something to cause this?

 

Probably air in the system . Go back to dealer and they will fix it .

 

I agree, they failed to properly bleed the cooling system. They were probably in a hurry to finish the job and got sloppy. They will fix it.

 

Thanks! Called the service manager and he said the same. It's at the dealer now and I'm driving a 2021 loaner, 11 year upgrade :-)