Long story short

Not to sound like I'm not on your side, but O'Reilly's doesn't make the parts they sell. The warranty clearly states that the part is warranted, not labor. That is the chance you take when you 'do it yourself' or DIY. If it is done in a shop where you pay for labor, you get a warranty on the labor as well, since you paid for it. When we have a part that has failed, we replace it under warranty, send it to O'Reilly or wherever we bought it from and file a labor claim. They send the part to the manufacturer for inspection. When they determine it was a manufacturing defect, they credit some of the labor to the part store who in turn credit us. That O'Reilly is doing that for you, an individual customer rather than a shop is unusual, but nice of them to do. You are getting as much as they are able to do. Anything man made can fail, and many parts are installed incorrectly and fail. That is why the manufacturer wants the part - to be sure it was them and not the installer. Otherwise every backyard hack that screws something up would be returning the part they destroyed as defective, and we have all seen that happen. I see a lot of backyard hacks throwing parts at a car to try to fix something they have no idea how to diagnose, then return the part when it doesn't fix their problem. Sorry, but you can't use my parts to diagnose your car! Point is, you bought a part, not labor and they are actually trying to help you out.