Mine was covered on my extended warranty. It took almost 2 weeks for the parts to come in. It seems to be on back order everywhere.I spoke to a mechanic at GMC and he told me the thermostat is not part of the power train warranty. Can anyone confirm if this is the case or not? I can't find this part in stock anywhere, including ebay, where some people have found it. I can't understand why such a common part like a thermostat is so hard to find.