2005 9-3 Linear, 87K miles. I had an issue where it was losing coolant and to make a very long story short, it turned out that the coolant was going into the oil, apparently due to a porous engine block. Mechanic managed to get the oil (sludge) out and put new oil in and we added GM seal tabs which seemed to help the coolant loss quite a bit. Everything seemed fine for about a month and now suddenly the car is losing oil at a very rapid rate. Mechanic says it is just do to the damage caused by having the sludge/oil starvation, says he has never even had a car engine survive after oil that looked like that, and he is surprised mine still runs at all. However, he says I should probably trade it in if I don't want to get a new engine, and that a new engine would cost about $4000 or so. He predicts that I will be adding 1-3 quarts of oil a week if I don't. Is there any hope or should I just try to drive it into a tree?