leave it original or replace parts?

[1776-1976-Eldo]

So here is the deal, new owner of a pretty much all original 76 Eldorado with 35K miles. My question is will I hurt the "authenticity" value of the car if I replace items that may be ready to go, or just aim to replace parts with the correct NOS parts? For example, having an issue with the generator light, checked the alternator (already a replacement) and it checks bad with no voltage output. I replaced with another rebuilt unit and now I am getting 14.7v. All good, and i am okay with that, but also had an overheat boil over at the same time. Looking at the lower portion of the radiator, the cooling fins are pretty corroded, and looking in the neck, I can see plenty of calcium buildup. Do I try to restore the original, replace with a NOS or just go with a better replica radiator? I did not buy the car as an investment, I want to put a few thousand miles on it a year, but still want to maintain it's value as an original. What advice can you provide?

[TJ Hopland]

With stuff you can fairly easily bolt on and off does it really matter what you use?   Keep the original stuff especially if its original to rebuild later if you or the next owner wants to or when you find someone and the money to have them rebuilt.

I believe US Radiator makes radiators for these cars with different options for cores from original to a fairly modern higher efficiency core but they are not cheap.   If you can find an old time radiator shop they too can re core them and they should also give you options for the type of core.   Last rad I did that was several years ago and not as large as a cad one cost me over $500.   Seems like someone here not too long ago said they spent $800.  I'm currently running a modern plastic aluminum one in my 73 and it seems to be doing fine.   Its not listed for that car,  I think only the Fleetwood Limo and 1 ton trucks but it fits and when I bought it it was only around $200.     

[James Landi]

I think, implicit in T.J.'s response: old Cadillac radiators require ATTENTION and often cause expensive engine damage during hot summer runs because they are partly plugged, and  we overlook them since they work ok during cool/cold weather--- so, if you can't get the original completely restored find the LARGEST capacity radiator that will fit. I've experienced some challenging road trips and damaged engines, especially because idiot lights on bright sunny days are hardly visible.   Another more subtle point, I've had two 70's Cadillacs where the lovely green coolant was decades old and the fluid ate through the engine freeze out plugs---don't assume anything is ok in your cooling system.... hope this is helpful,   James

[76eldo]

Get your original re-cored. It's expensive at about $600 but well worth it.
Keep it looking original under the hood.
An alternator is an easy swap on these cars and not as glaring j see the hood as an aluminum or plastic radiator.

A new radiator core will give you proper cooling for the car.

[bcroe]

if its for a museum display, just clean the crud off.  If you want to
drive it, get busy catching up the maintenance, which is PLENTY
on a car like that.  Everything that makes my 79 go has been
apart, long list of upgrades (SS exhaust, etc).  Bruce Roe

[1776-1976-Eldo]

I do want to drive it, so will look for someone in Dallas to do a re-core of the radiator. On the alternator change, it now puts out the correct voltage, but the generator light glows bright and dims if I turn certain things on like the AC, interior lights, etc. I suspect it is finding the wrong ground somewhere? Have not checked the fuses yet. Anyone run into this?

[hornetball]

Didn't know you were in Dallas.  Kirby's radiator shop in Ft. Worth.  A+++++++.  Old school shop that can do anything with your radiator for a really fair price.

Howdy from Granbury.

[Macabry]

"If you want to drive it, get busy catching up the maintenance, which is PLENTY on a car like that.  Everything that makes my 79 go has been apart, long list of upgrades"

Wise words Bruce,

I'd only add that NOS may be good/better for some parts,  but bear in mind that often they're 40+ years old and time rarely improves a parts condition (even is it looks "new") ...sometimes the cost of nos vs modern replacements can be high, which can mean for service parts your better off preempting part failure and replacing stuff with cheaper modern parts more frequently ... my two cents 👍

[71 Fleetwood]

I agree with making it run and staying original when it makes sense.  Currently, I have a set of YELLOW Accel spark plug wires because black were not available to tune the car.  They look so wrong 

[hornetball]

I installed a Vista-Pro 433165 on my 1974 (paid ~$340).  It's a 4-row copper brass in the correct early-70s GM form factor (all GM full-size cars and a lot of trucks used this radiator).  It cools well in our N. TX heat.

The only issue I had was that the overflow nipple was clocked incorrectly and the heater return was 5/8" instead of 3/4".  Probably an exact fit on an Impala, but needed a bit of work for the Eldorado.  Kirby's in Ft. Worth fixed both these issues for me and charged $45.

[J. Doogla]

I'm in the same boat....my 78 eldorado now has about 24k miles. The more I drive it, the more attention it needs. Currently waiting on power steering hoses. Aftermarket hoses don't have the foamy insulation stuff on them, like oe. But they will work just fine. Everything I replace, the oe part goes in the aftermarket box.
I'm getting quite a few boxes. Time stored and not drive is very hard on any kind of machine. In the motorcycle world, the saying for vintage bikes is "ride em, don't hide em" that applies to these cars as well

[James Landi]

"I'm in the same boat....my 78 eldorado now has about 24k miles. The more I drive it, the more attention it needs. "

You're so "on target" J.  We've hear of dozens of disappointed members with low odometer readings who believe their beloved vehicles are "time machines."  I purchased a Cadillac with 23,000 miles that, at the time, was 25 years old.  Fortunately, the several expensive failures occurred close to home and didn't cause extensive damage.  One can only wish that folks who market such slumbering beauties would factor these challenges into the price.  So many disappointments occur in such situations.   James

[76eldo]

Typical issues are radiators and heater cores in low mileage Eldorado's that sat for a long time without a coolant change.
Belts and hoses are suspect too although we have seen lots of older models from the 70's that have original hoses.
Axle boots are another item and of course the dreaded bumper fillers that crack and fall apart.

Whatever it needs, it's worth it.  The ride and enjoyment of owning a 76 convertible, especially a Bi-Centennial model far outweigh the work that the car may need.

Brian

[71 Fleetwood]

FWIW, my GEN light was helped by a 14 amp fuse to replace the 10 amp fuse.  cheap try.

[hornetball]

FWIW, my GEN light was helped by a 14 amp fuse to replace the 10 amp fuse.  cheap try.

This is a dangerous practice.  Fuses are sized to protect the wiring between the fuse and the load.  They are not sized to run the load.  If you run more current, the wire can overheat and, in an extreme case, cause a fire.

[bcroe]

Experience has shown, rebuilt alternators may not be perfect.  First
issue with the GEN light, make sure the alt has output current.  Next,
look for a bad diode, either the small trio or the main output.  Then
check that large voltage drops are not being caused by poor connections
in the battery distribution system.  Clean all this up and you have a
great system, sure beats a generator. 

The only fuse in an internally regulated alt sys is for the light, and it
takes a lot less than an amp.  A fusible link is good between the alt
output stud and the battery. 

My cars, which all have 70s engines and 60s transmissions, have been
driven quite reliably coast to coast, a million miles.  The key is timely
maintenance, BEFORE predictable things fail.  If you just drive it till it
breaks, it WILL break and not at a time or place convenient to you. 
Bruce Roe

[1776-1976-Eldo]

Put some work into the alternator today. Fuse was blown, so replaced. The correct size is 15@ which explains the post about the 10@ blowing. The GEN light was barely visible, but on. I checked voltage at the 2 pin connector, and it was showing low voltage on the inboard output that goes to the bulb. After about 10 minutes, it went dark enough that I could no longer say it was lit. I didn't follow up with another voltage check, but it may have been that the battery was a little low. I'm going to call it fixed for now since I am getting full charge voltage to the battery. I drove the car a few miles to warm it up, and did not get any overheat issues. I did not drive it on the highway, so I may still need to address my boil over issue later. I am having the time of my life fixing such minor issues, and driving the car. This is what I expected buying an old Caddy Another conquest was replacing the passenger rear ash tray assembly. It had a broken latch that made the door not open correctly. All fixed!

I don't have any leaks in the radiator, so I might research methods to acid flush the radiator out of the car and see how it goes before buying new, or a a re-core. The air conditioning will be after that. It worked "ok" when I drove it home from Florida, but leaked its Freon, and a recharge only lasted a few days. More on that later. Thanks for the support all.

[cadlove]

The cooling system answer is simple. Replace with like-for-like parts, BUT SERVICE PROPERLY. You also get to keep the original look.

So, the radiator, get it re-cored and order the same number of rows (top to bottom) and the same number of cores, typically 4. Cadillac also point out (with a/c) that you need to clean out the condenser fins with a soft brush.

Flush and back-flush the engine, thermostat out, same with the heater core. Use good quality heater hose and clamps, the best quality radiator hoses and clamps. Fit a new thermostat and use a coolant solution Cadillac request, mine being 50/50 water/ethylene glycol.

You can test the system if you want to, simply fit a temporary temperature gauge, take the car out along with a pal who can make notes on the time it takes to get the thermostat starting to open, then fully open, then running at full operating temperature. All of these  temperatures (usually) are listed in the Cadillac workshop manual. You need to own the right Cadillac manuals and Serviceman.

The car I have spends time on the french Riviera, slow traffic, a/c on, facing the sun at temperatures around 40C, that over 100F.

[V63]

Might also verify the cooling clutch fan! It may appear like it's turning but not pulling any air. I personally have no use for those and immediately exchange for a 'flex' fan. They do not fail. Check radiator cap as well, and t stat. The Easy stuff first.

[cadlove]

Apologies, I forgot a new radiator cap. Absolutely.

I replaced my fan clutch.

Sadly all of these fans make noise and sap power. I know folk that fit those double electric fans? Just don't like non-original stuff.

As I said previously, my car isn't a garage-queen, she lives in the real world and has had much use in hot places.

Going back to factory as Cadillac lay down is hard to better.