[sparcx]

I figured they were selling me some sort of line as a lot of vehicles these days have the cartridge style filters with the o-rings. In fact, some current generation Cadillac CTS and Chevy Camaros still use the same 3.5L intrigue oil filter. I believe it's why K&N and Mobil started making oil filters for our vehicle now.

You pretty much told me what i was expecting... that your 10 year old vehicle has never had an issue with a bad o-ring or leaking oil from the cap.
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I did check the Wix at the local o'reilly auto and it did have an o-ring included, but i have no idea if it's as good as the OEM version.

Out of curiosity, i checked gmpartsdirect and found some part numbers. If i found the right part number.... surprisingly enough this runs about $27 to replace when including shipping. (Engine Oil Filter Seal GM Part Number 12560846)

There's an oil filter cap part number for $31 shipped, but no idea if that includes the o-rings or not. (Engine Oil Filter Valve CAP GM Part Number 12553683)