My friend and I both unfortunately have Automatic Aveo5 hatchbacks, both 4 cylinders, hers is a 2011. I have replaced the thermostat, coolant resivoir, spark plugs, valve cover gasket, did two coolant flushes and now I did a tranny flush and filter change. Her coolant still has oily sludge in her new resivoir. There is no coolant mixing with the oil though. When I checked her tranny fluid it looked like a light brownish yellow, and honestly to me it looked like there was a hint of green to me...kinda confused...maybe a bad oil cooler? But she isn't overheating or loosing coolant anymore since I replaced all that. So I flushed the tranny fluid last night and it was black, mind you there is less than 100k on it. I cleaned it all up put on the new filter filled it back up and now when I pull the dip stick out it looks darker.
Her car is still having the same main issue, its hard for her to accelerate up hills, the rpms stay normal but it almost feels like its struggling to climbing the hill and will also do this at higher freeway speeds. No white smoke, no leaking, no coolant in her oil, no overheating, no check engine light or codes, oil light is on, I was going to do an oil change today but I wanna figure this out before I do a bunch of stuff that may turn out to be pointless in the end.