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1984 Eldorado help restore and rebuild

8K views 43 replies 18 participants last post by  KingEldo 
#1 ·
I just got a 1984 Eldorado Convertible Biarritz. Runs ok but it was shutting off on me after a 30+ minutes of driving. Local Mechanic did a engine pressure test / drove it around and told me I would need to rebuild my engine. I do need some restoration stuff on it too. I am in the Los Angeles area. Would anyone know where I can take my car to get a possible engine rebuild and get all the other nick nacks restored (some wiring, couple gauges, etc). I’m a new Cadillac owner and not sure if I should just go to a random mechanic or a Cadillac specialist. I want to fully restore this beauty and drive it around town and maybe some long distance trips safely. I would appreciate any help I can get.
 
#2 ·
Your car does not have a Northstar 4.6 liter V8 engine - it uses the small, low power 4.1 V8. It might be possible to swap in a 4.5 or 4.9 - lots of work.

Thread moved to the Seville/Eldorado forum.

Welcome Aboard !!!
 
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#3 ·
Johnny12... Congratulations, you are about to join the "spend a lot of money" club. If you have any mechanical ability, that is a plus, but the first thing you have to do is buy an OEM Factory Service Manual. Many of the little "nick nacks" you referred to can be addressed and solved by yourself with careful reading of the manual. While the 4.5 or 4.9 engine would be a welcome increase in power, the cost to change over from the 4.1 is probably not worth the effort. If you want to drive this car around without trying to drag race at every stoplight, just have the 4.1 rebuilt. Stay away from the sellers offering "rebuilt" or ""remanufactured" engines as most of them buy junk engines from recycling yards and just slap them together, they might run for a while but you don't know what you are getting. Your best bet is to find a responsible shop to reman your present engine. Don't forget, you have a 36 year old treasure which will need love and affection along with money and patience. Not too many guys around who will take the time to analyse any problems and fewer still who can do the repairs as they most likely were trained on the newer plug and play crap the manufacturers shove out there. This is a "tinker" car that demands constant attention and is a great cruiser and will turn a lot of heads wherever it goes.

You can find a lot of help on this site from those of us who have been through a lot of repairs and can assist you with first hand experience and knowledge and are willing to guide you through some difficult, seemingly impossible situations. If you really love the car and want our help, be certain to clearly explain the problems you encounter, pictures are helpful, as this is one of the first computerized efforts by Caddy and can be very frustrating at times. But don't let this scare you, it will be worth it to show it off when you cruise around the neighborhood. Good Luck!
 
#10 ·
Wow thanks for the awesome replies to my email. I don’t know too much as far as mechanical stuff, I do a lot of the restoration on the interior /exterior cosmetics parts of it. I purchased this car for $1650 from a guy that wanted the driveway space, willing to drop another $5k in total to get it in decent condition.
 
#7 ·
Hi Johnny, I second Scooter about the Factory Service Manual. Here's one for $15 on eBay: Original 1984 84 Cadillac Factory Service Manual Gas & Diesel W/Wiring Diagrams | eBay

Others, why would an HT4100 shut off after 30 minutes of driving?
One strong prospect is listed in the post above. 12-18 more things immediately come to mind on a 35-year old GM V8, but NONE of them involve or require rebuilding the engine. The best (actually the only reasonable) direction is for the OP to jump on the link you searched for him, and to take advantage of all the straightforward and orderly diagnostic routines related to troubleshooting driveability issues. It could be as simple as an electrical resistance build-up issue with wiring or ground(s) after the engine comes up to temp, any number of unattended routine maintenance procedures or parts, or.....
 
#6 ·
#13 ·
Fuel pump?



Do you mean compression test? What where the numbers?



A second opinion would not hurt.
Yes I am def taking it for a second and maybe a third opinion. He did not tell me any numbers, I will be taking it to get a second opinion from a mechanic who is a friend of a friend. Hopefully I can get a better answer on what needs to be done, will share.
 
#8 ·
#19 · (Edited)
You got that for $1,650?! Lmao, holy chit you scored!!![emoji2]

Damn that car looks Right! And it’s not very often you find these looking Right...

Looks similar to my 1st car, an 82’ except mine wasn’t convertible. I paid $1,300 and that was 23yrs. ago... For you to score that convertible for only $1,650 today is an absolute rarity. I dream of coming across a car like that for that price. Amazing.



By the way, I’m in Los Angeles too, in Wilmington. Where are you by?
 
#16 ·
I think you have misunderstood the mechanic or he is about to take you for a ride.

Regarding your budget, if the car needs serious help (paint, interior, mechanical odds and ends, NOT including an engine rebuild), 5000 will not scratch the surface of what needs to be done, especially if you are paying people to do the work. From your picture, the car looks to be in solid condition, definitely not in need of a restoration. Of course, not seeing the interior and the fact that most things look better in pictures could be clouding my judgement, but it looks like you got quite a deal for a convertible of the era.

Put up some more pictures and details of what the mechanics tell you. We'll help you assess condition and decide which way you want to go. These are not cars to restore, there are plenty of low mileage original pampered ones out there with virtually no issues available for not much more than your budget to purchase & repair this one.

Regarding your random stalling issue; in all likelihood you have a fuel or ignition component that is failing. Provide us with more details on what happens when it stalls. Are you moving, coasting to a stop, already stopped? Bucking/hesitation before it stalls? Probably best to create a new thread for this issue.
 
#22 ·
... or perhaps a failing TCC solenoid. Johnny, does the car stall after slowing down from highway speed?

Car looks very nice, by the way. $1650 sounds like a darn good deal. Particularly if you don't need an engine rebuild.
The car turns on just fine and drive great, but it will just turn off at a stop light (not while car is in motion), then I just start it again and it drives again. After about twice or three times of this, I usually just park it and wait (to avoid possible over heating ?)
I think I am going to get some more information from another mechanic and get more info on the issues and come back to share.
 
#23 ·
Nice car, Eldo2K. Very impressive first car.

Do you happen to know any reliable older mechanics around LA who might remember how to work on 80s Cadillacs?
I am actually looking for someone too, I came across “Ed’s Cadillac specialist” is Santa Monica but he seems to work on 50-60s cadillacs. Plus I am in Monterey park that’s too far for me.
 
#24 ·
I was asking about LA Caddy mechanics for a friend. That friend is you, buddy :) I'm on the east coast.

How fast were you going before these stop-light stalls? Over say, 45mph, followed by rapid deceleration, then engine struggles suddenly and also electrical struggles? Could be TCC solenoid. Happened to me, and those are the symptoms.
 
#26 ·
Ah I see, sorry. I appreciate that. No the car runs fine, the engine shuts off after about 20-30 min and it always shuts off when the car is stopped, like at a red light or a stop sign. Always turns back on and won’t turn off until I do another stop. But not on all stops. Going to take it to another a shop this week I ll see what he says.
 
#28 ·
ELDORADO2K... That looks looks like a Tiffany.. circa 1987 or thereabouts. Beautiful car. I've been looking for a 1983-1986 Golden Spirit for the past few years, similar to the Tiffany. Love the retro style but prices for these beauties are way out of line considering parts availability although the 5.0 Ford engine can be serviced almost anywhere. Post some more pics, enjoy drooling with envy over your prize.:):)
 
#29 ·
Johnny12...the engine shuts off after about 20-30 min and it always shuts off when the car is stopped, like at a red light or a stop sign. Always turns back on and won’t turn off until I do another stop. But not on all stops. Going to take it to another a shop

Still thinking about your problem, wondering if you have checked the basics like idle speed, vacuum as noted above, timing, air filter clogged, fuel filter and pressure (must have 9-12 psi), TPS and ISC motor to name a few. Before throwing a lot of money at it, do as scottelderado said, buy the manual, then clear all of the codes (the previous owner may not have done this for years), then drive it around for a few days which will set the latest info codes. Then you have a fresh start and can address which faults are current. This gives you a new slate of faults which are current and tell you where to look. This you can do at home and can direct your mechanic to the proper part or parts to check. Saves a lot of time and money when you know where to look.
 
#30 ·
Beautiful car and a nice score, bravo!
Not much I can add to what has been said except that my instinct tells me the stalling is an electrical problem. Old electrical components tend to fail when they get hot and 30 minutes sounds like the right time length for a weak component to get hot soaked and begin to fail. That said, Cadillacs are full of electrical components. One thing you might try to test the TCC solenoid theory is to put the car in neutral when you roll up to a stop. Even if the TCC solenoid is locked it won't kill the engine in neutral. The symptom of a locked TCC solenoid is exactly the same as rolling up to a stop in a stick shift car without pushing in the clutch. Also, I agree we need more data to help you effectively so do the onboard diagnostic and let us know what you find.
 
#36 ·
I would upgrade to an LS3 or if you dont mind spending extra, an LS7 or newer LTx, It will bolt up to the bell housing of your 4-speed THM440-T4 automatic You would have to get a PCM and possibly a BCM for your gauges etc. Chevrolet Performance might even have a complete package, with all electronics for between $15 and 17K. You would have the coolest Eldo around, and it would be very reliable. LS3's are great engines. This is what I would do instead of rebuilding an doggy old cadillac engine. You would be driving around with a big smile on your face and it would even get better gas mileage.


 
#41 ·
Long time Caddy fan here. Fine cars, Cadillacs. 50s sweet, 60s sweet, 70s mostly sweet, 80s awful. Just like all GM 80s cars. When yours was new it was a slow slug with all sorts of problems. IMO you'd be better off to find a more promising year. For the record some of the 2000 and later Cads were below par as well. Not very familiar with the 90s, but wasn't a fan of the look during those years. Think what you have there is a major money pit. A pretty one though. Just like a beautiful woman though, it'll likely just suck your wallet dry without much a a return on your investment.
 
#43 ·
I had a 84 eldo with the 4100, she was a perfect car, no rust, dents, rips. This was back in 97/98 my engine got really weak, and developed a knock. My dad had a good mechanic and my uncle was a good shade tree mechanic out of his garage. Both said it was impossible to rebuild that engine. Being it was all aluminum block. Maybe things have changed now? My uncle made an adapter plate for me for a sbc which was a carbed 305. Still had a/c, speedo worked fine, I kept the car for 9/10 more years. No issues, put a glass pack on it. With duel exit points. Sounded good. Still got over 20 mpg on the highway and except not having cruze. My favorite car by a longshot.
 
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