I'm working on a 2015 Malibu LTZ with the 2LT package that has the 2.0 LTG Engine (GTDI). Original owner, claims she had the oil changed based on oil life monitor each time with Mobil 1 synthetic. Currently has 73,000 miles. I changed her oil and filter with Amsoil SS 5W-30 and an Amsoil Ea filter at 68,000 miles. The oil that came out at 68,000 was super black and about 3 quarts low. At 5,000 miles, her engine is about the same level low (on the dipstick) so I'm guesstimating 2-3 quarts low. But this is with Amsoil SS 5W-30. When I first changed the Amsoil, the dipstick oil still looked black. Usually after a new oil change, the oil is clear/amber. There is signs of sludge/coking on the dipstick as well. The engine runs smooth and fast, but it also seems qualitatively hot. I can't touch the dipstick unless I wait like an hour after shutting off the engine. My other GTDI engines (Ford EcoBoost) don't have this problem. I read about piston failures due to "misfire" on the earlier ATS's with the same engine. Supposedly the Camaro has a different LTG engine. Any ideas? I'm thinking about going to 10W-30 or maybe a 10W-40/5W-40 oil from Amsoil, or perhaps Rotella T6 5W-40.