Fortunate to receive a very clean 1997 Deville, 40,000 miles. Has been sitting in a garage with lengthy periods of little use for about 10 years. Driven "occasionally" is all I was told. They put a new battery in it. After a few cranks, it fired right up. Engine bay like new. Was considering just selling it. But driving it back to Cincinnati (~450 miles), it was so clean, so comfy, and with no issues, I may have fallen in love with it.

Things I noticed and need to understand

1. Once started, the rear made some electronic whirring and clicking sounds. That auto suspension system waking up? Did it after a few more starts. Seems to have stopped for now.
2. Column shifter is a bit tough to move (yikes). I think it was slightly better when warmer. It was about 48 degrees at the time. I hope this won't be a huge deal to repair. Hoping mechanical, not transmission.
3. It wasn't very cold (~50 degrees), but the first 30 minutes of idling had a little light smoking from exhaust for a while. It wasn't super white oil burning smoke smoke; possibly normal exhaust hits cooler air, but it didn't stop for a while.
4. Used a basic Blue Driver ODB2 and it showed no codes.
5. Service Engine Soon light was on. Interestingly it went off driving home from Charleston to Cincinnati. But came back on near home.
6. Original whitewall tires. Unfortunately, thad evidence of dry rotting from not being used much.
7. Some shaking on braking, better with new tires. Still some brake shake at higher speeds. Hopefull just caliper pins need some love having not moved often.
8. Engine near new clean. Underneath signs of light oil and dirt accumulating at the bottom of the engine. No active drips. No stains on the garage floor.
9. The old fellow hit the passenger side view mirror backing out of the garage. Still on but loose. He had clear packing tape on it to hold it.
10. Notorious cheapskate, tight with a dollar. Trying to get any maintenance records from the dealer. Pretty sure he did a bunch of oil changes. Not sure of any of the suggested maintenance yet.
11. One record showed the Service Engine light on ~15K miles and they replaced ALL O2 sensors?

I put new tires on it in Charleston and had the oil changed. The only place open was Firestone. Not my favorite. The guy seemed to know a little about older cars. Said that sometimes, from sitting, the gaskets dry out and can start to leak when the engine is back in use. I wanted to do ATF change, but Firestone doesn't do that anymore, and I didn't want to mess with tranny fluid if the stiff column shifter was tranny related.

Any advice, known issues to look out for, experiences with hard-to-move column shifters, interpretation of Service Engine light, or things to do immediately for a sitting vehicle? Change all fluids?

Thanks everyone!

That'* a nice car. If decide to sell it let me know.

Moved from the "Pontiac Bonneville > 1992-1999" forum to the "Cadillac" forum.

I can understand that! It'* in amazing condition. Most of them have long since gone to the great valet lot in the sky.

I'm guessing you're right about this. Stick your head under there and make sure that the air shocks have the bladders inflated. If they're deflated, they'll shred themselves.


This is probably the shift cable is gummed up and/or going bad. When they are used normally, they keep themselves loose just by the tiny bit of wear they get. It might loosen up with use, but if not then it will need to be replaced. It needs to be properly diagnosed before taking my word for it. The easy way is usually to disconnect the transmission end of the cable from the shift arm and then see if the lever is still stiff or not.


Could have been either. After sitting that long, a valve guide is likely to have leaked a little.

If the OBD2 reader is showing connected and no codes while the check engine light is on, it'* time for a different OBD2 reader, even a super cheap one from Walmart.

I'd bet it is discovering itself after lots of slow use and then dead battery for years.

Shaking on braking is just about always warped rotors. Replace with new from a reputable brand. While you are doing this, you'll have it apart anyways. You can check for stuck calipers and clean/lube the pins.

They're still showing up in junkyards from time to time. Could maybe keep your eye out for a replacement mirror.

Always puzzles me a bit. Cheapskate but bought a Cadillac? Cheapskate so could afford a Cadillac? I'll continue to ponder.

Hopefully the dealership can get records for you. Often I have found that Carfax has a bunch of service data as well.

I'd believe it. Maybe it needed it. Maybe not. Auto Tech skill levels have gone down the tubes over the last few decades. I'm not saying all auto techs, but many. Almost all dealership experiences I've had in the last 20 years have been poor, and primarily because troubleshooting is becoming a lost art.

Not mine either, but better than a long drive on bad tires and old oil.

Yeah kind of. It'* not as prevalent as it used to be. Also, sometimes they just get old, and if it were driven all this time the gaskets might have gone out faster.

Good move. Better to not touch it since it was working okay, then have a real shop (or yourself if you're experienced) do this with quality parts and fluids.

Other stuff is above, and yeah change all fluids (even the engine oil again). Use reputable brand names and quality fluids. Keep an eye on the water pump. Change the belt, too.

I will keep that in mind.

Thanks for the help and replies.

ODB2: the ODB2 wouldnt show a code for a basic "Service Engine Soon maintenance light would it? Interestingly, the Service Engine Soon now is back off again. Must still be parsing data and learnign where it is after a long time asleep.

Day three findings:

1. Couldnt really get much air from dash vents using fans, plenty at feet. Wasnt readily apparant how to switch from feet, dash/feet, just dash. Hopefully not an actuator issue. But I also havent RTFM yet. Same for just setting it to outisde air only, no temp settings - raelly wants you run on Auto mode and use AC and engine heat at all time for temp control. Will read manual.
2. When setting it cool got a dash message "Air compressor turned off - Low refrigerant". Hopefully just, well, low - and not some other heting/cooling system gremlins from lack of use.
3. Small clunk from front passenger wheel area turning full left into parking space. Defintiely seemd basic suspension-like: tie rod, etc.

Willl update.

I take one issue at a time.
Do you not know how to switch between the defrost, floor and vents?

I take one issue at a time.
Do you not know how to switch between the defrost, floor and vents?
Let'* see a picture of your controller.
You should have something like this. You control fan speed and direction of flow from these buttons.

Im just noting issues as I find them, making my list.
My controls look like that picture. Sure its answered in manual. My brain is just used to the dial with pictures of air at feet, dash, or both ;^)

So is the mode door working correctly?