Is a 1998 Cadillac Seville a good car?

Whatever you could say about the car when it was new is now nearly irrelevant.

You're asking about a 20 year old vehicle. Realistically its best-before date has already come and gone and long time ago. How reliable it will be depends greatly on how well it was driven and maintained up until this point. That's not something anyone on Yahoo can answer for you.

As others have mentioned, the Northstar engine had more than its fair share of problems. That doesn't mean this example has problems, but the potential is certainly there...

Good for what? This car does not do good gas milage

It actaually sounds like a miracle. Best check the antifreeze level in the radiator and drive it long enough to make sure it's not over heating!

Co-worker got a rust free one with bad suspension for $300.

The Northstar engines were junk. Budget at least $1,000 for initial repair and about the same per year.

No, that is an old beater, a junkyard refugee that was a time bomb even when it was new. GM never could build a good aluminum engine, which the Northstar is. The last step on the assembly line is to add stop-leak to the radiator, since they know they could have porous castings. Everything on the car that can be automatic, is, and that's a lot of servos, dashpots and solenoids to fail...and they do fail. Leave that to be somebody else's problem.

Might be worth about $1500, but much more than that. However, you best have more cash to burn because you are guaranteed to need it for maintenance and repairs.

No.

Oh dear! Nice car; but I'm afraid you'll be buying a lot of problems.

No. Older Northstars have serious problems, especially oil leaks.

Possibly not