Oil Burner

hey, i have a 2.4L 97 sunfire. i have had the car for 6 months... or just shy of 6 months. this is my second oil change, the first time i had noticed the oil was exteremly dark; the girl who owned it previously also let the flex joint behind the exhaust manifold rot away. anyways, i put some high mileage castoroil in it, (140kMiles on it when bought, 150K now) well as i was changing it tonight i noticed that it was extremely dark, and this was 4.5k miles after my last oil change. said good for atleast 5000, or so i thought.

i poured out 2.5 quarts of bad oil, what makes itworse was i poured a quatt of oil in to it 2 week prior since my dipstick read 1 quart low.

My question is, how am i burning away the oil so fast? i dont have and muffler smoke at all, so im pretty sure its not going past the rings in to the combustion chambers.

i used castoroil again, but a different type. i am changing to a 3k mile change no matter what the bottle reads. Does anyone have any ideas tho?

Is it going in to your antifreeze ??? (IE:blown head gasket) I change mine around 6 to 7Km as I do 90% highway driving. 2001, 2.2l Sunfire.

Homerr