I am really surprised to hear so many good reviews on the 1984 Cadillac Coupe DeVille.
Unfortunately, mine was a different story long toward the end. I bought the car used in 1988 with 30,000 miles on it. I loved it, it was big, roomy, comfortable, smooth and quiet. The HT4100 wasn't a powerhouse, but it got the car up to speed pretty good.
I took the family to Florida to see Mickey in it in 1989, which was a 1,400 mile round trip. The car got us there and back with no problems.
In 1991, the thermostat failed and the car overheated in bumper to bumper traffic one afternoon. Thermostats are considered routine maintenance, so no big deal.
When hurricane Andrew was headed for Louisiana in 1992, we loaded up the Caddy and drove 800 miles North to stay with relatives. Again, car purred like a kitten there and back with no problems. I also made frequent road trips to Lafayette, Louisiana from New Orleans, which was a 250 mile round trip. I never encountered a problem on any of the trips.
In 1993, I moved the family to Orlando, Florida from New Orleans. I drove the moving truck while the wife and kids rode in the Cadillac. 650 miles was covered without incident. I believe the car had somewhere in the neighborhood of about 120,000 miles by this time, and was 9 years old. It continued to run reliably for the remainder of the year, but by 1994... it was beginning to get old really fast.
First, the computer failed, and the Cadillac dealer charged us a bloody fortune for a new one! I was hesitant to have the car repaired, but I believed that it would give us at least another several years of trouble-free service.
Next was the digital climate control. The dealer wanted an arm and a leg to repair, so we had it rigged by a shade-tree mechanic. The car was 10 years old, so we figured what the heck. The operation of the climate controls required the use of a 'toggle' switch, but worked nonetheless.
One night while we were cruising home from Wal-Mart at about 45-50 mph, the transmission dropped its gears. If you can imagine, this caused quite a jolt. At first we thought someone had rear-ended us! Thankfully, the car would still move, but wouldn't shift out of first. We 'limped' the rest of the way home in 1st gear. New transmission cost us $1500 for a re-manufactured unit. AAMCO replaced it. They explained to us that it looked as though an engine bushing had been lodged through it. I'm an idiot when it comes to automatic transmissions, so I accepted this. The car never really drove the same with the 'new' transmission. It had no get-up-and-go anymore. It almost felt as though the car was starting off in 2nd gear.
I decided to bring it back to AAMCO, and on my way there the darn thing broke down on me!
The engine stalled as I was coasting down the road. I pulled it off to the side and tried to crank it. The engine would crank, but wouldn't turn over. Rats! AAA came out and towed it to the local repair shop. Turned out to be the darn timing chain! The car had 136,000 miles. I decided I'd get the car fixed this one last time and then either sell it or trade it in for a better car.
I wound up driving the Cadillac for another year or so. I never even bothered to bring it back to AAMCO. Instead, I decided to live with it.
Everything held up mechanically, but it wasn't long before the interior started falling apart. The headliner was hanging down, the windows were falling off their tracks, the plastic wood panelings were coming unglued and falling off, the fuel gauge (located in the top-center of the dash) had a mind of it's own and of course the cassette player began eating tapes until it finally quit.
The final straw was in 1995 when the engine started burning a significant amount of oil out of the tail-pipe. I told my wife we're taking the car down and we're unloading it! I promised her a newer car, so she agreed for us to let 'blue boy' go.
We lost the driver's side hub cap on our way to the dealership. We arrived at the dealership and worked out a good deal on a 1992 Coupe DeVille (white with white/burgundy leather interior) Although they didn't give us much for the 84, I was glad to see it go!
The 92 had only 25,000 miles. I drove that car until 2002 and sold it with 180,000 miles. In my humble opinion, the 92 aged much more gracefully than the 84... and I didn't half as much trouble with it. The only 'major' item I replaced on the 92 was a starter at 150,000 miles. Everything else worked like a charm. The 4.9 V8 could run circles around the 4.1.
Well, that's my story!