1970 Coupe DeVille-any issues to look out for?

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Geeky1

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I'm considering replacing my '73 Riviera with a '70 DeVille. The car has ~100k, one owner, most/all service records, the original window sticker, etc., and it looks like it's always been garaged and appears to be in good shape. Is there anything in particular that breaks on these cars that I should be looking out for? I'm having the seller do compression and leakdown tests on it and a cooling system pressure test; I'm aware of the timing chain issue but that's not something that I can check before I buy it, practically speaking. I'll be driving it ~400 miles home, so I'll just have to hope that it holds together and have it replaced as soon as I can afford it after I get it here. But I can't think of anything else to do with it before I buy it from a mechanical inspection standpoint, short of driving it and making sure it runs properly.

It appears to be rust free but I'm figuring that since it's an early 70s GM product I should probably check around the back window and in the trunk particularly carefully.

Outside of that, and making sure that all of the accessories and power options work is there anything in particular that goes wrong with these cars that I can check before I buy it?

Any insight would be appreciated.

Thanks,
Kevin
 
Do yourself a favor and find a muffler shop local in the town your buying the car in & have them whip you up a 2 1/2" dual exaust with some loud mufflers. Then you'll REALLY enjoy your trip back, toastin' the hides at every stopsign for 400 miles, running down the hiway with the kick-ass roar of a 472. I'm completly jealous!

Caddy's are great cars, I would think that if you can drive it around for a few hours & it don't break or overheat(stuck thermostat may occur if it's sat around a long time) then your golden. Thats what I'd do anyway.

Just grab you AAA card & have fun!

-John
 
Thanks :) I'm kinda torn as to whether I should just take my AAA card or if I should try to get some tools and spare parts onto the plane (have to put it in checked baggage and hope nobody rips any of it off) with me. My plan was to take my IR thermometer, a flashlight and an inspection mirror with me at least. I was just going to check it over for leaks and rust, take a test drive, and make sure that it's staying at a reasonable temperature (~200*F??) when left idling with the a/c on...

I'm just not sure if I should do anything beyond that. On the one hand, I tend to think that some basic tools, a cut-to-fit gasket sheet, some belts and upper & lower hoses would be advisable, but on the other, the dealership selling it claims the car is absolutely perfect, and if the car looks like it's going to need any of that stuff, I won't buy it unless they knock the price down.

My major concerns for the drive back are one, it's going to have to make it over the grapevine outside of LA shortly after I've bought it, and two, I don't know if I trust the idiot light for the coolant temperature... Most people I've talked to seem to think that it's ill advised to hack up the upper radiator hose to temporarily install a coolant temperature gauge for the trip back, so I guess all I can do is keep it around 55 over the hill and run the heater just to be safe. Essentially, I've got concerns about a 40 year old car (pristine condition or not) leaving me stuck on the side of I5 on a saturday afternoon, and I'm not really sure what precautions I should take to prevent that.

And yeah, the dual exhaust is 2nd on the to do list after the timing chain. I may or may not do headers at the same time. But it's going to remain stock for a few months, unfortunately. :( I'm still not 100% sure it's a good idea to get rid of the Buick in favor of the Cadillac, but... The previous owner of the Riv didn't care for it very well, it just blew a head gasket, and it's cheaper to buy the DeVille-which I can drive and enjoy now, theoretically-then it is to build the Buick engine the way I'd want it built (600+hp). And if I were to fix the Buick I'd be left with a stupidly powerful engine in a car that still needs a complete restoration. I'm having a hard time justifying spending that kind of money on the Buick right now.

Out of curiosity, is there any chance of getting a limited slip diff into the Cadillac? And if so, what would it take? A custom corporate 12 bolt or Ford 9", or did Cadillac offer LSDs?

Thanks
 
Cadillac offered a LSD in 1970. Mostly in the Fleetwood '75 limo and the commercial chassis.
It's not really serviceable though. Best be it to fit a more common rear end.


You can check the timing chain. Pull the distributor and use a mirror to look at the cam sprocket. Look for the nylon cover and if it's they look for cracks and chips in the nylon.

FWIW, I drove mine 950 miles when I bought it. Only probably I had was the AC compressor locked up (no refrigerant).

I wouldn't try to take tools. But a some cheap stuff if you drive it. Find a Harbor Freight or similar early on the route. Some screwdrivers, a socket set, and some pliers. Maybe $20 in tools.


Things to check:
Other that the rust around the edges of the vinyl (under the trim, around the rear window) check around the front window too.
Check the floor pans, especially the back (have to check form underneath).
Check the lower rear of the the front fenders, between the wheel and the door.


Engine wise, check the TCS solenoid. Make sure you can get vacuum advance at the distributor (or bypass it all and run fom the carb to the dizy).
TCS prevents vacuum advance until 3rd gear.

Make sure the oil light functions. Or install a gauge. Sender/port is at the top rear of the block.
Same with the temp light. You could install a temp gauge in place of the thermal vacuum switch, at the front, drivers side of the block, below the distributor.

The heater/blower wont turn on until the engine warms up. Temperature sensor that prevents the fan from running when the engine is cold.

Try to inspect (have checked) the front suspension All bushings, ball joints, tie rod ends, idler arm, center link.

Check all the horns. Should be 3. Connect them one at a time and make sure they all work. Often one or more will be bad.


That's all I can think of for now.
 
STDog,

Thanks! :beer:

Good idea with the tools, I think that's probably what I'm going to end up doing. I'll talk to the dealer about having the distributor pulled and the gears inspected, I didn't realize you could inspect it that way. I'd do it myself, but there's no way I'd ever get it installed and running right afterwards (I know just enough about working on cars to be a danger to myself and those around me when I get beyond spark plugs and belts... :rolleyes: ), so may as well just ask them to take care of it. Might as well also have them verify that the oil pressure is correct.

How would I go about testing the TCS solenoid? I'm assuming based on a bit of googling and your description of its operation that it's not going to operate with the car in park or neutral... Anything that would show up on a test drive if it wasn't operating properly?

As far as the warning lights go, Is my memory correct that they should all come on with the key in position 2 but the engine shut off, and then go out when it's started?

Thanks again for the info!
 
Geeky1 said:
I know just enough about working on cars to be a danger to myself and those around me when I get beyond spark plugs and belts... :rolleyes: )
Click to expand...

Are you sure you want a 38 year old car?

Get a copy of the shop manual quick, before the trip if possible. (one of the CD version and a laptop?)
A lot of good information in there. Wiring diagrams, diagnosis charts, etc. could be real handy if you're not confident in you abilities and knowledge.

How would I go about testing the TCS solenoid? I'm assuming based on a bit of googling and your description of its operation that it's not going to operate with the car in park or neutral... Anything that would show up on a test drive if it wasn't operating properly?
Click to expand...
Doubt you'll find much on Google.
I won't have a chance to look it up before Saturday. Min's been bypassed for a few year now. The solenoid broke :(




As far as the warning lights go, Is my memory correct that they should all come on with the key in position 2 but the engine shut off, and then go out when it's started?
Click to expand...

I don't remember exactly. It's in the manual though. There's a slot in the glove box door to hold the owner's manual so it's usually with the car.
 
Do I want a 38 year old car? Yeah, I do. I've been into cars since I was a kid, so I have a pretty good understanding (I think) of how things work, I just never had an opportunity when I was growing up to really wrench on anything. This is going to be a learning experience.

I just got the #s back from the dealer on the compression test, they're saying 150psi across the board. I'm not sure what the spec on this engine is... but they're even, at least.

I was holding off on purchasing a shop manual until I got some information from the dealership that indicates that it's in as good a shape as they claim it is-something beyond their word, that is-but yeah, I need to go ahead and pick one up. Looks like they're all over ebay.
 
Geeky1 said:
Do I want a 38 year old car? Yeah, I do. I've been into cars since I was a kid, so I have a pretty good understanding (I think) of how things work, I just never had an opportunity when I was growing up to really wrench on anything. This is going to be a learning experience.
Click to expand...

Just making sure.

For someone not confident in their skills, it can be a headache. No way to do it if you're paying someone else to do all the tweaking/tuning (unless you've got big bucks). And heading out on a 400+mile trip is an invitation to Murphy.

Case in point when I left Miami with mine, I got about 2 hours north when the compressor locked up and I losyt power steering. Then spent 2 hours to get the right belt to bypass the compressor.

I've known many that got 30+ yr old cars and weren't ready for the challenges.
 
STDog said:
Case in point when I left Miami with mine, I got about 2 hours north when the compressor locked up and I losyt power steering. Then spent 2 hours to get the right belt to bypass the compressor.
Click to expand...

You spent time looking for a belt? The same thing happened to me but I just arm wrestled the Eldo the rest of the way. My forearms looked like Popeye by the time I got home. lol

Geeky1, good luck with the Deville. And don't worry 'bout not being an expert. That's the beauty of this board. They have the brains, you provide the labor. :thumbup:

Eric
 
hertzdaddy said:
You spent time looking for a belt? The same thing happened to me but I just arm wrestled the Eldo the rest of the way. My forearms looked like Popeye by the time I got home. lol
Click to expand...

Yeah. I had 1000 miles 14+hour trip. I wanted my PS back!
 
Thanks for the tips guys. Flying down there late tomorrow morning to look at the car. As long as it's in the condition it's supposed to be in I ought to have it home tomorrow night. I made up a checklist of things to check on the car. Between the checklist (and accompanying clipboard), the flashlight, and the inspection mirror, the dealership is going to think I'm  :screwy: But that's ok.

And, as a bonus, it looks like the weather in LA is going to stay in the low 70s tomorrow, and it'll only get cooler as I go up the hill. I'll probably go ahead and put some water wetter in it and keep the A/C off over the grapevine, but if the car has been cared for as well as it supposedly has, I doubt that there will be any problems. Either way I'll post back with pictures or that I didn't buy it for one reason or another, if anyone is interested.
 
Well, I looked at car, found the water pump failing. The dealer replaced the pump while I waited and I finally left around 9:30pm. Made it 60 miles, pulled off the freeway to check things over, brake pedal went to the floor. The car stopped, but only just. If I'd gone over the other side of the hill things would not have been good. I don't know what I'm going to do at this point. I need to sleep on it.
 
Change master cylinder "bench bleed w/ line disconnected" you'll probably be surprised to find you can connect the lines and you'll have brakes without even bleeding the wheels. then drive on home, its all part of the getting to know you you process(How much do you love me?!) seems like all my old bones would do that to me at least once, my old '67 beetle left me in the dark on a deserted stretch of road@ 0230,( loose wire at the regulator under the seat) After that never did more than hiccup, always took me home , even if it was ailing. Same storey with all my caddy's, Good Luck!
 
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