72 Eldorado Engine - Rebuild or Replace?

[abriddell]

Hello,

My 72 Eldorado convertible (187,000 mi) is leaking oil, burning oil, and leaking transmission fluid.  None of these issues make the car un-drivable.  I just check the levels each time before I take the car out.  I particularly enjoy backing through the puff of blue smoke that usually accompanies the first start-up of the weekend as I back out of the garage.  Ah, the smells of summer... : )

I would like to correct these problems, but I don't have the expertise or equipment to do it myself. 

The engine was rebuilt in 1993 (129,000 mi), with (quoting from the invoice): "New lifters, rings, rod and mains bearings, cam, timing set, oil pump, & reworked heads"  There is also a line item for "1 used motor for bad block and head," which I'm assuming is from a sacrificial engine that was used for part of the rebuild.     

Unfortunately the car was driven for just a few years and then pretty much just sat in a garage 2004 until it came to me in 2011. 

A local reputable garage quoted me a range of $5000 - $7500 to pull the engine and transmission, and either rebuild the engine onsite or send it out for a remanufacture, depending on what the surgery revealed.  Their notes say:

Has multiple external engine & transmission leaks. Engine also has internal problem/damage causing smoke from tailpipe. (Pinton rings or valve guides) Suggest Engine/transmission removal and engine dismantel to correct problem. Estimate depends on machine work needed. Transmission front seal leaking, also needs external resealed & new axle shafts.

Estimate Range 5000-7500 Complete.

Remove engine and disassemble. Have necessary machine work done depending on damage/wear once disassembled. Re- assemble engine with all new gaskets. Have exhaust manifolds resurfaced flat. Replace transmission front seal, pan gasket and differential axle seals. Replace both c.v. shafts.

Does anyone have any advice on rebuilding the existing engine vs. replacing it with a remanufactured one from a reliable source?  I would also appreciate some advice on what those sources might be, please. 

Thanks very much for your help,

Andrew Briddell
McFarland, Wisconsin (near Madison)

PS- This isn't a show car, but I've had some bodywork done and had it repainted.  I'm not all that concerned about number matching everything.  It's just a fun car to drive and it's been in the family since the mid- 70's, so it's also sentimental.  Photo is attached...

[Bobby B]

Andrew,
   WHEW!  A lot going on in your post...If the first engine rebuild was done to a high standard, it should have lasted over 60K miles if taken care of properly. Did you know Exactly what was done the first time? Do you know anything regarding the internals of an engine, how it works, what questions to ask, and how to know if they're doing unnecessary work, proper work, and to what level? Are they re-using components or replacing. I've said it a hundred times...There are rebuilds and there are REBUILDS. I wouldn't touch that engine until you got an honest opinion, and had a proper compression and leak down test done. Leaks have nothing to do with wear and tear and puffs of smoke out your tailpipe on start-up. Maybe new valve seals, and a complete re-seal is in order. Maybe at the very worst, the compression is great but the heads need a re-freshining. At 5-7K, I would be asking A LOT of questions as to what I'm getting for my money, so it doesn't hit the 10K mark by the time you're done, all in. New Pistons? New Cam/ lifters or Re-ground? New Valves/ Guides or Knurled and cleaned up. New oil pump or rebuilt? Balanced? Etc., etc. etc....Get some more info on this before you dive in. And Re-sealing vs. re-building a Trans are two totally different things. 5-7K isn't a bad price if done correctly, but make sure you know the extent of the rebuild and what you're getting for the money, IN WRITING......
                                                                                Bobby
P.S. Where's your old block and heads? Did you check this engine to see what year it was from? Didn't the old shop call you first regarding the condition of your existing engine before going ahead and substituting with "Used".

[bcroe]

There is no way that engine should need a rebuild again.  Check the valve stem
seals, which can be changed with engine in the car.  Don't do anything till the
oil leak is determined 

Again determine the exact leak point on the trans.  I suppose the "front seal"
is the one behind the torque converter.  The biggest leak problem with these
TH425s is the chain cover. The fix of favor is forget the original gasket and use
gasket forming GLUE to seal the chain cover.  This usually requires removing
the trans.  The rest of the leak points are repairable in the car. 

HOWEVER, if the trans wasn't renewed at the same time as the engine, its
way overdue.  Fix it before it blows and reduce the damage done.  I put a
$30 seal & gasket kit in mine periodically, but the labor to take it apart is
about the same as a full rebuild if you can't do it yourself.  good luck, Bruce Roe

[abriddell]

Thanks, Bruce and Bobby for the quick replies!

Yes, lot's going on in the post... sorry about that.  Here's the history that I know...

My uncle owned the car until he died in 2006.  I have his steno book full of notes and a file of invoices.  The one from 1993 that I mentioned in the first post says, "Rebuild motor and replace trans. front seal."  I'm assuming all of the items listed as "new" were, in fact, new, but I don't have much else to go on.  The steno notes indicate that there were still some problems with leaking lifter(s)" a couple of months after the rebuild, but then that theme disappears.  I have no idea what happened to the old block and heads.  That was all done in Cincinnati 25 years ago...

I have a passing understanding of how the engine works, but I'm not a mechanic my any means.  I'm guessing that seals dried up and started to seep/leak when the car wasn't riven regularly for that 6-8 year period. The estimate from the local shop includes this:

LEFT NEW CV COMPLETE ASSEMBLY   $187.58
Right New CV Complete Assembly      $187.58
MISC,FLUIDS, SEALS, PARTS             $300.00
AXLE SHAFT SEALS (2.00)                   $44.60
TRANSMISSION SEALS, KIT               $168.75
Full Gasket Set                                 $224.58
PISTON RING SET                             $227.92

Labor: $3,291.75 Parts: $1,341.01 Sublet:$0.00 Job Total: $4,632.76

There is no mention of new pistons, rods, valves, lifters, etc. on my estimate write-up.  That number does seem very high to me without a complete replacement of the guts of the engine and reboring the block.  BUT... I've never been down this rabbit hole and that's why I thought I'd better ask for some guidance.   

Sounds like the first questions I should be asking are to run a compression test and leak down test, and isolate the exact sources of the leaks.  What else should I be asking, besides "what exactly am I getting for my rebuild fee?"

Thanks again,
Andrew

[Bobby B]

Andrew,
Hi. At least you have some paperwork to go by. A piston ring set and re-ringing, is by no means any way, shape, or form, considered a "rebuild". First of all, trying to get by with possibly slapping some oversize rings in, is a short-lived poor man's way of stopping blow by. Also regarding that subject is the finish on the cylinder wall referred to as "Honing". Again, there are correct finishes as per ring type/ manufacturer spec, and then there's some shade tree mechanic running a ball/stone hone in your cylinder without the proper fluid, trying to guess at when it's the proper time to pull the hone out  of the bore with the correct finish. Hones come in many different sizes for different applications and that needs to be adhered to. I would never go that route if I wanted the car to be right and last any amount of time. Your poor Uncle didn't get a rebuild from those ticket items you listed. He had some drivetrain work done and some additional band-aid work with it, that was WAY overpriced. If you want to do this engine up right, you're going to need some good honest advice as you go along. Just out of curiosity, what area do you live in?
                                                                                                                   Bobby

[abriddell]

Hi Bobby,

I live in McFarland, WI, which is just outside of Madison.

You should see all the old notes... it looks like a medical record!  It's been fun going through all of that stuff.  I'm being very cautious and trying to become very well informed as I get into this project. 

He paid $2000 in 1993 for "New lifters, rings, rod and mains bearings, cam, timing set, oil pump, & reworked heads"

The quote I received ($4600 as written, $5000-7000 estimated depending on what they found once the engine was disassembled) was to "Remove engine and disassemble. Have necessary machine work done depending on damage/wear once disassembled. Re- assemble engine with all new gaskets. Have exhaust manifolds resurfaced flat. Replace transmission front seal, pan gasket and differential axle seals. Replace both c.v. shafts."

Andrew

[The Tassie Devil(le)]

I agree that the first thing that should be done is the Compression Test, both dry, and then wet.

Have a really good look to see where all the leaks are, and as with the Eldorado, to properly fix leaks, the engine and transmission will have to come out, especially is the sump and the transmission chain cover is leaking.

Hopefully, someone local might be able to assist, as there is nothing better than having a second pair of eyes.

The thought of the Axles requiring replacement really needs looking into, as if it is only the rubber boots that are leaking/torn, then these can be replaced, without the need to buy new axles.

The CV Joints are VERY strong, and the only way these can go bad is if the grease has gone from the boots, and dirt got inside.

Take lots of pictures and post them.

Bruce.

[bcroe]

If you apply an original style set of gaskets to the TH425 trans you will
no doubt soon have an original style leak at the chain cover.  The GMC
people advised me to instead glue that cover back with some of this and
a simple procedure.  Been working on my TH425 for a long time. 

Some other trans leaks are caused by rust destroying the seal, and the
rust must be cleaned up before it destroys a replacement seal. 

The seals around the clutch pistons inside will not cause any drips, but
a failure could cause loss of pressure, a burned up clutch pack, and
poison circulated through what was a nice trans.  Bruce Roe

[Bobby B]

He paid $2000 in 1993 for "New lifters, rings, rod and mains bearings, cam, timing set, oil pump, & reworked heads"

Ok. I misunderstood when you said only "New Rings". Even with all that work done (had it been done properly), you should not be smoking and whatever else you have going on. #1 priority now is a Leak Down & Compression test to see where you're going with this. Maybe it'll be good news for a change and not as bad as you think. Does it run fine with a decent amount of power, regardless of the hemorraging?
                                                                                                              Bobby

[Jeff Rosansky CLC #28373]

Let me ask a few questions from a different angle.

Tell us about this shop. Oil changes, etc are one thing
Rebuilding an engine is another. I took mine to a very well respected engine shop and he still made mistakes. This isn't a 350 Chevy.  If you decide to have this done, please be sure this is the correct place to do the work. Don't have the shop learn about a 500 on YOUR dime.
At a minimum the shop should wash down the engine and drive it around the block to see where it is leaking. In hi school I had an old Mercury that left well over a quart on the ground every week. Everyone told me to pull the engine and do what you are talking about. My shop teacher told me to check the oil sending unit. That was it.
Point being-find out what your problem is first and go from there. If the shop just says multiple leaks with no more real detail they they are not the right place.
Jeff

[Roger Zimmermann]

My shop teacher told me to check the oil sending unit. That was it.

Ah! Jeff...When I was just to deliver my '56 de Ville, this car was behing the 2 others. I had to take all 3 out of the garage and let them idle outside for 5-10 minutes (it was end of November, almost freezing). Put the Brougham first into the garage, then the Biarritz and lastly, the de Ville. I was glad it went without problem and I closed the garage door. Then I noticed an ugly oil trace on the driveway. Opened the door, looked under the de Ville to see a large puddle of oil on the floor. Jacked te front of the car, let the engine run and saw the oil dripping at the rear of the engine. At that time, I was sure that the leak was at the rear seal, even if it was a rubber one. Told it to the customer, lowered the price by $ 1000.00 and gave him an oil pan seal and a new rear seal.
He told me later that it was the oil pressure sending unit!

[chrisntam]

snip...
I was sure that the leak was at the rear seal, even if it was a rubber one. Told it to the customer, lowered the price by $ 1000.00 and gave him an oil pan seal and a new rear seal.

He told me later that it was the oil pressure sending unit!

And the customer sent $900 back to you?

[Roger Zimmermann]

And the customer sent $900 back to you?

Oh no! he claim to have spent that amount to let replace that sending unit...He does not gave me back the oil pan gasket set nor the rear seal but, as I has the impression that with about $ 37'000.00 I did a good sale, I'm "clean".

[abriddell]

Bobby asked,
"Does it run fine with a decent amount of power, regardless of the hemorrhaging?"

Yes, it runs nicely.  I don't have any trouble getting up to speed on an onramp or accelerating to pass another car.  In fact, it runs great at 75 mph on the highway.  If anything, I go easier on the acceleration than what the car has to give.

Compression and leak down test... that will be very interesting to see what turns up. 

Andrew Briddell

[The Tassie Devil(le)]

Mine ran beautifully at 75 MPH on the Massachusetts Freeway, and everywhere else, but when I pulled the engine down when I got home, the timing chain was totally worn out, and all the nylon teeth were missing.

Oh, yes, I had lots of little oil leaks, which is the reason I pulled the engine.   To replace the gaskets and clean it up, plus replace the Welsh Plugs.   Didn't notice the chain till I removed the cover.

These engines will run forever, no matter how old or worn out they are.

Bruce.

PS.   Plus I repacked the CV Joints.

[Jay Friedman]

My own Cadillac is a '49, so I don't know much about '72s and won't add a single word of a technical nature to what everyone has said so far.  However, in reading their postings, I get the impression that you may be in need of someone there in Wisconsin who could direct you to a reputable shop which has some experience with cars like yours.  A very knowledgable guy in the '40s Cadillac world is Jack Hoffman, who lives in Horicon, Wisconsin, and who is a CLC Technician (Mechanical) for 40-49 Cadillacs.  I have no idea if Jack would deal with a '72 problem, but he may very well know of a person or a shop in your area who could help.  His contact info is on page 58 of the CLC directory. 

[abriddell]

I ran a compression test today, using a new INNOVA 3614 tester.   I warmed the car up for about 10 minutes, shut it off, then tested each cylinder dry (6 revs).  I recorded the results, and then repeated the test wet.  I added three squirts of oil from a little oiler canister to each cylinder and then cranked the engine.

The pressure gauge topped out after 5 revs on all tests.  I ran each test twice per cylinder.  There were no differences on the dry tests.  During the wet tests, cylinders 2 and 7 both had different first and second readings.  I added 2 squirts of oil and ran a third test.  I recorded all three results, in sequence, in the chart, below. 

Shop manual specs: 165-185 psi at cranking speed with throttle open.

My compression test results:

#1  Dry: 150   Wet: 180
#2  Dry: 180   Wet: 195/190/195 (three tests, wet)
#3  Dry: 180   Wet: 195
#4  Dry: 180   Wet: 185
#5  Dry: 179   Wet: 180
#6  Dry: 155   Wet: 160
#7  Dry: 151   Wet: 170/165/170 (three tests, wet)
#8  Dry: 155   Wet: 160

I haven't done a leak down test yet - I don't have the equipment.

Any thoughts as to how to interpret these results?

Thanks,
Andrew Briddell

[TJ Hopland]

Those numbers don't look much like a low mine rebuild.   Must not have been a good quality rebuild or its had a hard life since.  Those numbers are not that bad overall.  I have definitely seen a lot worse that still ran well. 

[abriddell]

"Hard life since...."  it sat for about 7 years with minimal, if any driving.

[Bobby B]

Those numbers are not that bad overall.  I have definitely seen a lot worse that still ran well.

I agree. Not great, but not the end of the world. The bottom end is OK. Wait until you get a 0-20 reading    ...........
                                                                                                                                                          Bobby