I did the first oil change today at 1,470 miles and the only thing unusual was when I removed the cartridge filter the top seal for the cartridge stayed with the housing top when I removed it. My 2008 CTS had the same style filter and I did many changes (more frequent than the OLM system indicated) and never saw this before. So for those of you doing your own filter changes make sure the cartridge seals come out with the cartridge.

At 1,470 the filter paper was a bit darkened but there was no obvious buildup so things are looking good. I have to pick up the proper lube for the differential which will get changed over the weekend.

Oil changes on the ATS are much easier than they were on the CTS since it doesn't have the bottom cover below the engine that has to be at least partially removed (4 bolts in the back and push pins in the front, changes without removal cause oil to drain onto the cover). It is also easier to avoid the cats on the ATS, I have a small scar on my wrist to commemorate my first CTS oil change. The errant rubber seal removed easily from the top cover and now the ATS has 6 quarts of fresh Mobil 1 and is ready to go.