The other week I get a call from my step dad asking if I could take a look at my step brothers 08 Cadillac CTS 3.6L. He bought it used a couple months ago, and all of the sudden the car starting making a "sewing machine like noise" under load. First thing I asked was was their oil on the dipstick? He said it was completely full on the dipstick. Started driving it, right away it sounded like a sewing machine. I could tell that it was also missing while speeding up. Go to Walmart and check the oil. Well yes its full before wiping the dipstick. After wiping the dipstick and reinserting, no oil . Go into walmart buy 2 quarts of Supertech 10w30 and a KN filter oil filter (cheapest one). So I could get it home and change the oil. Put the 2 quarts in and it brings it up just to the LOW level. Get home change the oil and checked the OLM, it had like 3% left. Put some of my clearance Pennzoil 10W-30 HM Syn and the KN on it. The oil sticker said change the oil 10,000 miles ago, so probably 13,000 OCI. Oil came out darker than crude. Filter came out just fine, no sparkles or sludge. So I told him to change it every 3k and I would do it for him to save some money (he just had a kid and I think he's still going to school). I bought some of these filters on RA. They came with no box. I looked them up on and I saw that they should be made in Poland not China. So are these actually Carquest/Wix or not? For next oil change i'm contemplating on using Sam's Club Prime Series 10w-30 as the main oil. Do the 3.6s like 10w-30?