I have owned 4, fourth generation (1983-1987) Monte Carlo SS's. So I will give a write up on what went wrong with the previous Monte Carlo, the one that I had the longest, rather than the new one I bought 2 weeks ago.
I bought the car with 80,000 miles on the clock, it was a beautiful 1988 Super Sport, very good condition, two previous owners.. one gentleman who bought the car new and sold it to his nephew in 1991, the 2nd owner babied the car, garage queen, etc. So I bought the car for $3,200 and that was an extremely high price for the car, but it was at a dealer. and I was desperate to get rid of what I was driving so they took a trade in and $2,400. Within the first month I had it (not getting it checked out by a mechanic--mistake) I took it on a road trip to Philadelphia, on the way home my water pump blew out. So that cost me 600$ installed also got new belts and a tune up.
Between 80k miles and 125k miles, I did not have one problem with it... before I got rid of the car, the only thing that wore down was the torque converter. The engine and drivetrain for the most part was still strong. I feel that I got my 3000$ worth driving this car for 4 years, with only a 600$ repair and routine maintenance. I did sell this car to another monte carlo guy, he is 'restoring' it so to speak, not that it needs too much, but can be made better.
This car, nothing, just bought it. 28,000 original miles on the clock, It was owned by an older gentleman who did not drive it very often, then a police officer for a short time, and sold it to me. I highly doubt anything is going to go wrong with it, provided it's taken care of, which it will be, until between 80,000-120,000. At that point they will need routine service, as any car with that many miles would need.
Great car. Reliable car. They are very solid cars, Very affordable car that will hold up extremely well if taken care of, and will last many many many years to come. A bargain of a classic car, as the turbo regals & grand nationals became more desireable and collectible. IMO this is one of the best looking cars Chevy has ever produced. The bucket seats are very comfortable, very roomy, I'm 6'2" and have plenty of leg room. They handle very well, even at high speeds. A decent amount of power as well, stock. However, the 305 can be built to produce a respectable amount of power if you wish. But if you want a car that moves and have the money, you'd be better off buying a turbo regal or grand national. If you want to own the last of the full size, real wheel drive, 4 barrel carb, V8 Chevy cars, before the revolution of front wheel drive, aerodynamic, emission friendly, plastic automobiles hit, do yourself a favor, and buy yourself a 1983-1988 Monte Carlo SS~