: Starting Long-Stored Coupe DeVille

06-28-07, 12:20 PM
Hi all,

My 93-year-old aunt just gave me her 1974 Cadillac DeVille. It's been stored in dry, clean, showroom like conditions since 1998 when my aunt quit driving.

I called the local Cadillac dealership and asked for advice on starting a car that hasn't been started in 9 years. They said it would be good to drain the fuel tank and replace with regular gas. They also said to pour a small amount of gas into the carbuerator, turn the key, and "see what happened."

I'd like to hear suggestions from some who have had similar experiences. Also, would like advice on where to buy a battery for this car. Dealer said they could order one.

Thank you.

06-28-07, 01:46 PM
Wow, I hope the engine isn't locked up after that long. I wouldn't spend a lot on a battery for this until you know it will even start (thus, I will forgo my normal glowing endorsement of an Optima Red Top) and just buy something halfway decent at an auto parts store.

Better yet, maybe you can use a battery out of another car (even if the fit isn't right on, as long as the ampacity is enough it will work) so you can save $60+ on a new battery until you know it will actually run.

Make sure the oil level is ok before cranking, and if it runs, change the oil in short order afterwards. Once you get her going, with the engine running make sure you look under the hood for signs of belts or hoses that might let go - rubber parts may not hold up well after sitting this long. Coolant should also be changed before you put any major running time on the engine.

Brake hoses (and metal brake lines for that matter) would be suspect not only from storage but the age of the car. Being a safety issue, make sure you have these checked before driving the car more than a short distance (say to get it to a nearby shop for inspection). Also inspect the outside of the fuel tank (from under the car). Cars this old have metal tanks, make sure there is no rust/corrosion that may cause leaks.

That's about all I can add, maybe some older school Cadillac owner's can chime in (I'm driving a 95) as I don't know much about carb'd engines - I imagine there may be some trouble there (sticking float, glazed up?) having been sitting for almost 10 years. Might help to have a can of starter fluid on hand, and a helper to spray it while you are turning the key.

Let us know how the resuscitation goes.


06-28-07, 04:38 PM
I'd say prime the oil pump before you start it. 9 years is a long time for the oil to still be in the valvetrain.


06-28-07, 04:43 PM
May I suggest that you remove the spark plugs and inject a bit of Seafoam into each cylinder. Allow this to sit for several hours. While you have the plugs out replace them. After the alloted time, crank the engine over a few time. Because there is no compression the engine should turn over easily.

Install the new plugs but pull the coil wire. If the air cleaner is not already off, remove it. While someone cranks the engine and pumps the accelerator rapidly, look into the carb and see if it is getting fuel. If fuel is present reconnect the coil wire and attempt to start the motor. When it starts only give it enough pedal to keep it running. This will allow the oil pressure to rise and the engine warm up a bit.

You might have to spray some carb cleaner and run some fuel additive through it for about 100 miles or so. change the fuel filters, oil and filter.

You may get lucky and she will run smoothly. If not, don't panic and start changing parts. Wait until you are satisfied that fuel system is clean before you start looking for other problems.

DopeStar 156
06-29-07, 12:58 AM
'74...... is that the 472 or the 500?

The Ape Man
06-30-07, 08:41 AM
Change the engine oil and filter.
Drain and disgard the old gasoline. A siphon using the hose connected to the fuel pump inlet will work for this. Inspect the gas. If the old gas isn't mixed with sludge then simply refill the tank. If there is sludge in the old gas then the tank might need cleaning. Depends on the gas and it's age. I've seen 5 year old gas run small engines OK. This isn't usually the case. Also had a boat with 11 year old gas that turned into a mixture of varnish and clear liquid. That stuff was really bad news and would have really messed up an automotive engine.
All rubber fuel lines and filters should be changed. You can run the engine for a few minutes with the old coolant thermostat to make sure things are OK before spending money. The thermostat should not be trusted after sitting for a long time and needs to be replaced before running the engine longer than about 3 minutes. You can top the coolant with water for now because it will be getting changed. Don't leave it like this during cold times of the season or things will start popping.
The carbonator will probably need a rebuild but you can initially try a start if you keep a close eye out for signs of flooding. Always beware of losing your eyebrows to a carby flashover when running unknown engines with the air cleaner housing removed.
Pull out the plugs and squirt some lube down into each cylinder. Transmission fluid works for this. A couple ounces into each cylinder is plenty. Disable the spark as there will be fumes which can ignite. Hold the throttle wide open while cranking the engine over with the starter. This will prevent gasoline vapors from filling up the exhaust system. A lot of mechanics skip this part. Not a good idea though. The engine should spin very quickly with the plugs out. This will allow the oil pump to circulate oil to the lifters which might be an issue. Oil pump prime should still be fine as long as nothing was taken apart. You can crank it for a solid minute at a time and let it rest for 15 minutes with the plugs out. The stuff you squirted down into the cylinders might shoot back out so protect anything that you don't want oil sprayed on. During and after the 1 minute crank you will be looking at the carbonator for signs of flooding unless you have decided to rebuild it. Gas will pour out of different places if the carb is shot.
Check for signs of oil pressure. Either the dash idiot lamp will go out or you can hook a VOM to the oil pressure sending unit to verify pressure.
If you made it this far then reconnect the spark, install the plugs and try to start the thing with a fire extinguisher nearby just in case.
When it lights try to keep it running at about 2000 RPM for enough time to shut up any lifter noises. A minute of 2 should be OK. Keep an eye out for burning rodent nests flying out of the tailpipe.
Good luck.

06-30-07, 04:06 PM
Thats what also happened to me, except this sat for 6 years and started right up with a new battery.