New owner of a 85 eldorado!!!

[98deville]

Just got me an 85 eldorado Conv. with 87k original miles on it and wanted to know what services as far as tune ups should be done?

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[Cadillac Jim]

That is a magnificent car. Only 2300 were made. The VIN should be of the form 1G6EL678XE6nnnnn where X is the check digit. This was the last year that Cadillac made their own convertibles. The 1992-2003 Eldorado convertibles are made from the coupe by a bodyworks by arrangement with Cadillac.

I have a check list for any used car. Its based on the idea that I buy a car to drive it every day. The list:

• Oil change with new oil filter, and lube any suspension fittings that are regularly serviced. Washer fluid, power steering fluid, and ATF levels should be checked. New air cleaner element is a good idea.
• New wiper blades.
• New belts and hoses, and a coolant flush and new coolant.
• Walk around the car and find and replace any burnt-out bulbs. Sneakiest culprits are the rear license plate lights.
• Front end alignment.
• Check the tires for condition, correct size and type, and, on the axle with the differential (the front for your car), matched rolling radius. Mismatched front tires can destroy the transaxle if you run on them too long.
• Battery check.
• I would consider servicing the transmission, then flushing it to get Dextron VI in it for better shifting and longer life.
• A new full tank of top-tier gasoline.

As soon as everything is done I would take it on a short road trip. With fresh top-tier gasoline you clear the cobwebs out of the engine. Any little things that need attention come up when driving quietly along at 70 mph.

Check out the top carefully. In my limited experience with my wife's 1991 Sunbird convertible, a convertible needs a new top every four or five years. Unless you know when the top was last replaced, you can probably assume that it has one or two good years in it. If it has tears that show up when the top is up, the end is near.

Other items you might look at are plugs (AC/Delco R42CLTS6) and wires, new high-brightness headlight bulbs, and checking the headlight alignment. If you have the FE2 suspension or the Touring package, high-performance tires is a good match to the car; you can keep that in mind when you buy tires in the future.

And, finally, drive it over to my place so I can take pictures of it.

[WarrenJ]

VERY pretty! Many happy miles.

[scott y]

That is one FINE looking Eldorado....

[KHE]

Very nice car! The most important service item in the HT-4100 engine is to keep the coolant changed every two years and use the GM coolant sealant pellets since the 4100 engine is a wet sleeve design.

Never flush an automatic transmission - that has been discussed at length on this forum. Drain and refill of the trans. fluid is the proper service method.

The last year of production Cadillac convertables was 1976. The 1984 and 1985 Eldorados were conversions by a coachbuilder company.

I'd see the dealer about a replacement hood ornament - if it has been discontinued, you can get the part no. and possibly find it on the GM restoration parts site or ebay.

[CoupeDTS]

Beautiful car!!

I have to tell you a scary story though.

I had the HT4100 in my 83 deville. It had 93k miles on it and ran fine. It was a very babied car so I had no doubt the engine was as solid as the car. I was planning on going on some long trips so I decided to give it a good tuneup. New rotor, cap, coil, ignition module, plug wires, plugs, oil change, o2 sensor, open element air filter, fuel filter, pcv valve, true dual exhaust (done a few months earlier), there was a few other things I cant remember it all. Well after doing all this I drove it around the block and it only made it halfway before a piston broke off its rod and cracked the cylinder wall sleeve which dumped coolant in the crankcase. Basically major engine failure. To this day I dont know what went wrong but it felt unusually strong that half block I drove it. Maybe a good tuneup was just too much for that old engine?

My point is if its not broke it might be best not to fix it. Just like trannys work best with the gunky fluid in there already rather than new thinner cleaner fluid. Belts are good to change and hoses. I still do tuneups but that experience makes me think twice about what I do. It was also a waste of money all those parts I just put in it lol. This engine was one of the worst engines ever made you have to realize so dont expect it to last forever. Mechanics hated these motors. Aluminum block, aluminum intake, aluminum pistons, it just had alot of issues because it was new technology. The whole block weighs 30lbs, I have a picture of me holding mine in one hand lol. One thing I noticed when I disassemble mine was there are tons of bolts that hold the intake on the block and heads. Every single bolt was hand tight. So at first I thought that is why it failed but the gasket was still sealed. It was a piston failure maybe from oil pressures or better spark creating better combustion chamber pressures I dont know.

I say just drive it and enjoy it for awhile before you mess with it too much!

[Cadillac Jim]

I would venture that whatever killed CoupeDTS's HT4100 wasn't the tune-up. Throwing a rod results from complete oiling failure and usually but not always comes with some warning, however slight. By the sound of the post, it might have been the piston pin seizing or the piston seizing in the bore, again a result of complete oiling failure on at least that cylinder.

I once had this happen to me when I was a teenager, driving my father's 1957 Plymouth station wagon, a small V8. I heard a squeaking noise from under the hood but the car was running fine, so I didn't know what to make of it. When I stopped at a traffic light I saw the oil light come on so I shut it down and called for a tow. A pull-down revealed that one or more pistons was dry and was in the process of seizing in the bore, and apparently this was the squeaking noise. The root cause was failure of a main bearing which stopped oil flow to the bottom of one or both the two adjacent pairs of rod journals, and thus to between one and four pistons and piston pins.

One very common problem that I have seen in older cars is metal debris in the oil from cross-threading the oil filler plug, then using a self-tapping filler plug for a fix. Over seven years, my 1959 Chevrolet lost two engines to this; the 235 CID inline six didn't have a full-flow oil filter. But an engine that did have a modern oiling system, a 327 cid V8, fell to the same fate; I heard a faint main knock and found that the *dealer* had put in a self-tapping oil plug, and, yes, my high-performance tri-metal main bearings were scored, at least one of them badly enough for a sensitive ear to pick up a main bearing thump. I rescued this one with new bearings, oil pump, and oil pan.

[coolnesss]

I'd add two things to Jim's excellent list.

1. Locate each vacuum tube under the hood and under the dash that you can get to. Snip off 1/2" or so from the end of each one and reattach it. Over years, the ends become hard and brittle, and snipping off that end gives a fresh new seal. It's easy and free. Vacuum is important to those old cars.

2. Get a can of WD-40 and a spray can of White Lithium Grease. Spend an hour or so going from one end of the car to the other, lubricating each and every moving part that you can reach. I spray WD into the dash controls, for instance - the levers that control the A/C, and into the switches - this restores smooth movement in alot of areas. Make sure you lubricate the hinges on the top. This goes for the throttle connections, the wingnut for the air cleaner - everywhere that something moves on the car. I'd pull each electrical connection plug under the hood and give each one a spritz also.

I had an '84 Eldo and it was one of my favorite cars. I used Marvel Mystery Oil in the fuel one time when it was running poorly and had spent alot of dough on mechanics that didn't change anything - and it cleared up the condition in a couple of tanks of gas. The rumor was that those engines can build up carbon and the MMO applied once in a while clears that up. It sure did on mine.

[BodybyFisher]

Beautiful car, I would just go through the car and see what it needs and change all fluids, good luck with it, it's beautiful!

[adallak]

Nice find! Love solid and classy looks of Cadillacs from 70s and 80s.

[lothos]

very beautiful car, I really like these and want one eventually

[winterset]

Inspect all the metal fuel & brake lines for rust. you might want to wire brush any light surface rust, wipe it down, and give the lines a good spray with WD-40 as well. also, spray the brake bleader bolts & line bolts with liquid wrench. after a few days, open the bleeders, and have someone help you pump the brakes & keep filling the Master with new brake fluid. If it hasn't been changed in a while, it'll probably be black or brown.

[CarlaValentine]

That is one gorgeous car!! I think I'm jealous.

[adallak]

To this day I dont know what went wrong but it felt unusually strong that half block I drove it. Maybe a good tuneup was just too much for that old engine?

You cracked me up! I call tune-ups "screw-ups".

[WarrenJ]

This engine was one of the worst engines ever made . . . .

Everyone has a story. Mine is the same, but also different than yours.

My '83 Coupe D'Elegance launched its HT4100 around 60K miles (kinda guessing here). The camshaft gave it up and took out the front of the block. $1100 later the bone yard swung a used engine in and I drove trouble free for another 30K miles before I sold it in flawless condition to a fellow who had no concept of how to baby a car.

I ran into the owner a few years later. The car looked like it hadn't been washed since the day he took possession. He explained his frequent trips to Canada had racked up enough miles to put the odometer over 220K miles. His son said it was the finest used car his old man had ever owned.

Go figure.

[KHE]

This engine was one of the worst engines ever made . . . .

Everyone has a story. Mine is the same, but also different than yours.

My '83 Coupe D'Elegance launched its HT4100 around 60K miles (kinda guessing here). The camshaft gave it up and took out the front of the block. $1100 later the bone yard swung a used engine in and I drove trouble free for another 30K miles before I sold it in flawless condition to a fellow who had no concept of how to baby a car.

I ran into the owner a few years later. The car looked like it hadn't been washed since the day he took possession. He explained his frequent trips to Canada had racked up enough miles to put the odometer over 220K miles. His son said it was the finest used car his old man had ever owned.

Go figure.

The key to longevity of the HT-4100 engine was frequent coolant changes and the use of the GM sealant pellets. We had an '85 Fleetwood Brougham d'Elegance - beautiful car. The button tufted leather interior was the finest, most elegant interior of ANY car I have ever seen. Sold it with 190,000 on it and the guy who bought it ran it well past 250,000 miles. A friend had 172,000 on his '84 Coupe DeVille when he sold it in the early 1990s.

[Cadillac Jim]

I once knew some people who bought a new Ford mid-size with an inline OHV six-cylinder, about 1968. I saw them walking alongside the road about 8:00 PM one evening and picked them up. They said that their new car had simply quit running while they were cruising down the road at about 40 mph. I offered to go look at it and we drove to their car, which had been coasted around a corner and off the road.

They popped the hood and I shined my flashlight around, expecting to find a distributor wire off the coil or some such... but I saw a cam lobe sticking through the block. I closed the hood and took them home, explaining very gently that they needed to call the dealer in the morning and have them look at it, and what they would find.

These things do happen. They are rare but in point of fact the oiling system of most engines is really only third or fourth generation. Oil is pumped to two main galleries, one to the valve lifters on OHV engines or to the heads in OHC engines, the other to the main bearings. From the main bearings, oil flows through the crankshaft to the rod bearings, and from there to holes in the rods that squirt measured amounts of oil up to the cylinder walls and perhaps to the piston pins. On OHV engines the oil from the lifters goes up through the pushrods and lubricates the rocker arms and valve stems. On OHC engines the oil from the gallery on each head lubricates the cam bearings and the lifters, and leakage is metered to control flow and allow lubrication of the valve stems and tappets. Sometimes restrictions that look like carburetor jets control the relative amounts of oil that go to different galleries.

Anywhere in that system debris can cause oil starvation or bearing damage. The debris can be anything that gets past the oil filter, and when the engine is cold a check valve can let astonishingly large debris past. The debris can clog a passage, or score a bearing and cause a loss of oil flow past that point in that particular oil path, and debris that is itself generated from a scored bearing may continue and cause more oiling problems downstream. Most engines are significantly over-oiled so nothing may happen until the obstruction is cleared or maybe forever. But if a total oil starvation happens somewhere, the bearings or pistons will seize. This kind of thing is most common with new or newly rebuilt engines, which is why they are all run before new cars or rebuilt engines are delivered. The next most vulnerable period is after any kind of service in which the oil is disturbed, like right after an oil change.

A good policy is to start the engine and let it idle until it warms up after an oil change. This keeps the oil pump from opening the check valve around the oil filter, giving it the best possible chance to catch any debris introduced in the oil change, or any pre-existing debris or hard sludge washed down from the heads when the oil is poured into the cam/valve covers.

[Texas Jim]

I had a 1984 Fleetwood Brougham deElegance...

White with button tufted blue leather and white viny; top.

Beautiful car.

Bought new in Dec 1983 and sold in Dec 2001.

18 years and over 250,000 miles.

The only engine trouble I ever had was a leaking HG at about 150,000 miles..

I put a quart of LIQUID GLASS in it and never had any more engine trouble from it at all.

Still didn't use any oil when I sold it.

[jndnaps]

Just got me an 85 eldorado Conv. with 87k original miles on it and wanted to know what services as far as tune ups should be done?

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That's sweet! I love that body style. I had an 84 triple white Eldo. The timing chain broke and the motor blew. I ended up selling it and buying a 96 Diamond white Eldo.. I should have kept it. Good luck with it.

[adallak]

Looks like Cadillac did not put the best engine in those gorgeous cars. HT stood for High Technology.

http://en.wikipedia.org/wiki/Cadillac_V8_engine

http://www.popularhotrodding.com/features/0408phr_worst_automobile_engines/index.html

[WarrenJ]

. . . The button tufted leather interior was the finest, most elegant interior of ANY car I have ever seen.

Amen!

[Cadillac Jim]

IMHO the HT4100 was a fine engine - for a car about 500 pounds lighter than the cars that it ended up in. There was a lot of confusion about the downsizing trends of the time. How did that mismatch come about? Well, Roger Smith was CEO from 1981 through 1990. If he had ordered a 5.0 liter to be built instead of a 4.1 liter, it might have been a whole different world. But most cars of the 1980's were less than sterling performers.