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1973 Eldorado Engine Rebuild

Started by BBlackstone, April 26, 2021, 04:13:39 PM

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BBlackstone

My '73 Eldorado runs really smoothly, but the thing drinks oil and coolant unfortunately. I'm thinking it is time for a rebuild after almost 50 years. Is there any way around this? It's really costly and time consuming and seems like a big headache to me. Any input is much appreciated. Thanks.

-Ben
1973 Cadillac Eldorado

MaR

Quote from: BBlackstone on April 26, 2021, 04:13:39 PM
My '73 Eldorado runs really smoothly, but the thing drinks oil and coolant unfortunately. I'm thinking it is time for a rebuild after almost 50 years. Is there any way around this? It's really costly and time consuming and seems like a big headache to me. Any input is much appreciated. Thanks.

-Ben
Are you getting coolant in the oil and/or vice versa? What are the condition of the plugs? Do they show oil fouling? Have you done a compression test?

TJ Hopland

How much oil and coolant we talking about here?    And does some end up on the ground or bottom of the car?   Or just magically goes away?

Looking at the plugs is a good idea.   IF they are extra clean that points to a head gasket issue which is pretty rare on these motors.    IF they are kinda crusty that is rings and maybe a little valve guide seals. 

Rebuilding one of these isn't easy or cheap.   Once you find someone to do the work you can't do there tends to be a lot of might as wells that really add up cost wise.   I did mine maybe 10 years ago now and even doing some work myself I think I easily had 3K into it the first time and another 1k after it ate itself due to a dud oil pump.  10 years later its again kinda a leaky mess.   I kinda wonder if I would have been better off to just do the timing chain and some seals and call er good. 
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

BBlackstone

I'd say I have to add another quart of oil about once a month and a good amount of coolant. Honestly seems like its mainly coolant that's magically disappearing, but both are not leaking outside the car. No leakage on the ground or undercarriage. I'll take a look at the plugs. I don't want to ignore the problem but at the same time I don't want to wait until it gets worse. Thanks for the advice.

-Ben
1973 Cadillac Eldorado

TJ Hopland

How many miles are you usually putting on in a month?

Quick head gasket test would be on a dead cold engine would be to open the radiator cap to make sure there is no pressure in the system.   Replace the cap then give the top radiator hose a squeeze to calibrate your hand what no pressure feels like.  If you are sensitive to hot things wear a glove and wear it on the test too so you know what it feels like.   

Start the engine and let it warm up.  Keep checking the upper hose for pressure.  Beware of the fan, belts, and that it will be getting hot.  Pressure should not build till the heat starts to build which should take several minutes and may not even happen without driving it.    IF the hose gets fairly hard before the temp builds that is a sign of a head gasket issue.   Combustion gasses pushing into the cooling system which also means it could suck some in on the intake stroke.       
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

Caddylackn

white tailpipe smoke is also a sign that you are burning a little coolant.  You can also smell it.  They make these funnel coolant filling kits that you seal to the radiator cap let you bring the reservoir level above the radiator, this makes it very easy to see any bubbles from combustion and signs of a bad head gasket. https://www.amazon.com/OEMTOOLS-87009-No-Spill-Coolant-Filling/dp/B01A2CQSU6 .  This is also the best way to fill a radiator and purge out air in the system with the motor running.  Hopefully it is just a small head gasket leak, that has failed between the head gasket firing ring and a coolant passage.  You need to fix this now before it becomes a big failure and leaves you stranded or hydro locks the motor.  The oil consumption has me worried.

Before making a commitment to rebuild the motor, first take cylinder compression readings, and/or a leak down test, and then oil pressure readings at idle and cruising rpms.  To rebuild your existing motor I would budget at least $4,000, which is $2k for parts and shipping, and another $2k for labor and machining and misc.  I would remove the motor and disassemble myself and take it to a machine shop, but would pay somebody to assemble it to a short or long block unless you have experience with this.  Then paint it and install it myself.  Another option would be to swap in a decent running used motor after resealing it and giving it a new timing chain, valve seals, and an oil pan clean up.  Save your original motor though.
'61 Fleetwood 60- owned for 31 years
'61 Series 62 2-door - sold
'64 Series 62 2-door -sold
'67 Sedan De Ville - sold
'74 Eldorado Convertible - sold

kkkaiser

you can rent a tool from the auto stores that  you put on your radiator top to see if any gasses are escaping through the coolant system.. dont know the name of the tool, but you put this fluid in this tube, put in inlace of the the radiator cap, and turn on,, ( follow actual directions but this is a recap of what i remember), if the fluid turns one color, you have exhaust gas in your coolant, if not, you are clear.

"Cadillac Kid" Greg Surfas 15364

Ben
I would do the compression/leak down testing first. If it shows the rings are in good shape I would plan on pulling the heads.  Alive seals and valve guide wear are a very likely cause for the oil consumption, and it would not surprise me to find a cracked cylinder head to be the cause of the coolant usage. With luck it MIGHT  e a head gasket. While at it timing gears/chain replacement would be prudent.
Greg Surfas
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-