she's a 1989 760t wagon.
i've got a choice. to junk the car, to fix the car ($$$) or to just run it till it drops. here's the problem. for a while the engine has been running weak, and blah blah blah. i did a tune up (cap, rotor, plugs) and noticed when i pulled out the plugs that the farther back i went (cylinder wise) the worse the plugs were (oil drenched wise). so i did a compression test on it. it registered 150 on all, except the second cylinder which read 135, but aparantly anything over 125 is okay, so i dropped it. i am told that if the rings aren't leaking, then the oil is coming from the leaking valve seals. now, to replace that, there would be a great amount involved totalling to about a grand. is there anything i can do to help with the leak without ripping apart the block? all i can think of is using 20w50 instead of 10w40, but i don't think much help will come from it. she's a great car, i don't want to trade it in.
any help would be greatly appreciated.

thanks