This car has been very dependable with no MAJOR repairs.
Very fast with nice take off, and feels like you're floating on a cloud. Very spacious inside with soft seats. Smooth steering, and you can also use the climate control for vehicle diagnostics; you just have to look up the codes for a direction to start looking for what's wrong.
This car still runs smooth, and I haven't had any issues with the transmission slipping in quite a while. I would drive to a stop sign, then when I would try to drive off, it would not move. If I put it in neutral then back into drive, it would catch and be fine. Recently it was losing about 3/4 of the oil after an oil change or topping off in a day. I was told where it could be coming from, but I don't feel like pulling the engine apart to replace the gasket.
The right bank O2 sensor will go bad if you run into any big puddle. They don't have to be deep; just enough to make a nice splash, and water will get inside the connector. It took a while to figure out why they were going bad, but eventually it was solved. Water gets into the connector through the wire inputs of the harness. When this happens, the car will chug, backfire, almost stall when taking off, and misfire to where you can hear a clunk in the engine. Crazy that an O2 sensor can make you think your engine is gonna blow on you any second. After driving about 20 minutes, the car will stop showing symptoms. I've read the sensor goes into closed loop mode.
The factory headlight switch burns on these vehicles. I looked for another switch in the junk yard, and all of them were also charred with melted harness. A friend of mine had this happen in his Impala around my year also. I bought a store replacement, but it doesn't click right, and within a year the headlights went out and the switch looks fine, so I wired a relay to trigger the headlights with the parking lights.
The door panels have fallen apart badly on the driver's side, and the passenger side handle broke off.
Rear passenger axle bearing was bad on this for a while, until I looked around and read about this being a problem with Roadmasters. The axle sits on the bearings, and over time they dig a groove into the axle. You can buy a replacement bearing with a sleeve to sit on the axle, and it sits a little farther forward to avoid rubbing the old groove. To get the axle out, you must use a brass hammer or a board and a hammer to hit the hub (don't be afraid to swing hard). That will knock it in so you can remove the C clip holding the axle inside. You're looking at a few hours of work, but not a hard job. When I removed the pin holding the differential, it got a dig into it holding it in, making for about an hour job to loosen it out. I think this pin had to be removed before knocking the axle in.
Heater blender actuator went at about 235k. You'll hear a creaking noise in the dash, randomly behind the radio it sounds like. I believe it's the door trying to open.
Exhaust manifold gaskets weren't bad, but it's nice to have someone to hold them up while bolting.
The seam from the driver's edge of the trunk to the back window rusted and let a lot of water into the trunk. I tried to seal it with 3M body seam sealer, but I think it rusted too far back and leaks badly.
The driver's front wheel lugs snapped once, with only one surviving and the tire hanging on. Another times 2 or 3 broke. Another time, most of them loosened up. I can't find a reason why they were doing that.
Hood cable froze in the winter, and in the summer broke. I replaced it, and it broke in the car, and constantly comes out of the handle, so I have to hold it while pulling the lever.
Fuel pump died randomly driving down the road. Restarted a few times, then gave out. The car has a lot of miles, so if it's the original, I have no complaints.
When I have the door lock's fuse plugged in, the interior lights won't turn off. I have wired in a toggle switch to lock the door, because I didn't feel like chasing down the problem.
Driver's door window will not roll down. I can hear the motor clicking, but the window doesn't roll down. At one time only the passenger window was only working, so I replaced all the switches and the problem went away.
A common problem on these also is the VATS system. DO NOT buy a new ignition cylinder or steering column. For me, I measured the resistance on my key, then went to the steering column and cut the VATS wires (two tiny white wires) in the orange sleeve and soldered in a resistor to eliminate the key problem.
The heater blower also is an issue in these a mechanic told me. The way the connector is mounted causes them to break connection over time, and the new ones have a pig tail connecter to eliminate that.
The car has never left me stranded, and the motor still runs quiet like it has few miles on it. I'm sure it has many more in it, but the fuel in the city is horrible. I spend about 40-60 dollars a week just on driving to work and my other trips, which isn't much driving.
If you are not mechanically inclined, then this car could cost you a bit of money on repairs. The life and dependability of this motor makes it worth the hassles here and there. I don't know if I'd ever own another, but just a heads up of what to beware of when buying one of these.