For service and parts needs, visit your dealer/retailer.
You will receive genuine GM parts and GM-trained and supported service people.
Genuine GM parts have one of these marks:

Accessories and ModificationsChevrolet Cobalt Service & Repair Manual. Heater Core, Replace
1.
Apply park brake.
2.
Shift transmission into neutral.
3.
Remove console shift lever bezel by
carefully lifting up around outside edge.
4.
Unsnap shift boot from front console
...