Andrew Tipton

In February i bought a 2015 Silverado Z71 5.3 with 67K miles. Last week i dropped it off at the dealership bc i was getting the coolant smell when i got out of my truck. I gave them the bulletin number #PI1513A after they checked my truck over yep the radiator and thermostat has to be replaced. They are trying to fork me with the whole bill, Is this not covered under the power train warranty? I'd love to get some help on this. Thank you in advance.