used car buying comparisons

I'm looking to buy a "new" volvo in the next two months, something in the 1-2,000 dollar price range for a college car. I'm currently looking at the pricing on 88-91 240s, 740s, and 940s and was wondering what the significant differences or problems might be. Currently I own an 81 240 which has all the usual gremlins attached to it, leaking windshield, wipers don't turn off, but lately it's picked up the annoying habit of not starting about 5% of the time and not amount of cajoling will work, it still gets 27mpg highway and leaks a quart every 3,000 so I plan on driving it through the winter. But it's time for it to go. So what are some of the major disfunctions/disadvantages to the different models. About all I know so far is that rust seems to be the predominant demise of most Volvos so the next one is coming from CT or PA and not salty NY. Any advice on whats better or what specifically to watch for I'd appreciate any answers. And if anyone knows how to make an old 240 start every time that'd be just as good. So far I've tried a new ignition coil(old one was water filled, don't know how it worked), distributer cap and roter, spark plugs, spark plub wires, and the two wires leading to the ignition coil to no success, the pump can be heard pressurizing the line after it's sat for awhile and weather doesn't concern it. Thanx in advance. -Russ