Overheated 472... turns slowly

[Faded Crest]

Hi guys, need your thoughts on this one...

I'm going this weekend to look at a '73 SDV that is supposed to be very low miles and in great cosmetic condition. Problem is about 3 or 4 years ago, the previous owner overheated it and drove the car home red hot. After that, it wouldn't spin fast enough to start again. They said the had it checked and there was no water in the oil at all.

I know that conventional wisdom would say it's a rod bearing, but In my younger days, I had a stuck thermostat on a '76 Cadi with a 500 and ran it so hot that it quit! And after it cooled down, it cranked right back up like nothing happened.

What do you think? As tough as those Cadi big blocks are, I have a hard time believing it is a rod bearing. I've heard of plenty fo those things getting red hot and being okay.

What do you think the chances of success would be if I removed the spark plugs, filled the holes with marvel mystery oil and ran it around for a minute? Think that would free it up?

If not, would it be feasible to do just the rod bearings?

Thanks,
Marc

[drmenard]

I think if he got it home and it was still running and not knocking you have a good chance its ok.... Get it running and see what it sounds like...

[Faded Crest]

Saw the car, it's very, very nice. Also got to talk with the guy more about it. He already tried all the tricks. Removed spark plugs, pickled the cylinder holes with Mystery oil, and tried to run it around... no dice. Of course, I couldn't hear how fast it turned, but he said it spun too slowly to fire. He has a friend who works at the local Cadillac dealership as a mechanic. He looked at it and said he was sure the bearings were swollen, and too tight to turn. Good news is that compression is good and he thinks the top half is fine with 71K mi.

I'm ambivalent over the deal. The car is beautiful, the interior is almost like new and the body is amazing. I thought it was a Sedan de Ville I was going to look at, but it turns out to be a Coupe! Even better. I could easily forget the car if it wasn't in such amazing 1-owner condition. Garaged it's entire life until 4 months ago. He is set on $1,800 as it sits. His mechanic estimates $500-$1,000 to replace the rod and main bearings. I'd buy it in a second for $1,000, but he won't go that low. I really hate buying a non-running car, especially when over $500 has to be spent just to hear what it's going to sound like!

I'll be praying over it. Thanks guys.
Marc

[cadillac_al]

If I liked the color, it would be very tempting because it wouldn't be hard to just put another 472/500 in there. I'm a sucker for a beautiful mint interior. I do like the 73's more than any of the later models.

[SpecialFX]

I think the ad expired on here, but I have a 73 coupe deville that I'd like to get rid of due to buying a house and wedding expenses.

Don't mean to threadjack. You owe us a pics thread if you end up picking it up!

[zonie77]

Originally Posted by Faded Crest

I know that conventional wisdom would say it's a rod bearing,


Marc

I've never heard that. Overheating usually causes piston/ring/cyl wall problems.

So with a good battery in it it spins fast enough for a compression test? How did your mechanic friend test it?

[Faded Crest]

Originally Posted by zonie77

I've never heard that. Overheating usually causes piston/ring/cyl wall problems.

So with a good battery in it it spins fast enough for a compression test? How did your mechanic friend test it?

I've heard that over the years, though I'm no mechanic. I am open to any new ideas if you have another theory.

But with the money it would take to fix it, you could just about drop another good-running 472 in it and be done.

Marc

[Faded Crest]

Originally Posted by cadillac_al

If I liked the color, it would be very tempting because it wouldn't be hard to just put another 472/500 in there. I'm a sucker for a beautiful mint interior. I do like the 73's more than any of the later models.

It is a pale seafoam green metallic with brocade interior. One of those combinations you would either love or hate. I actually like it.

Perfect dash, perfect carpet, perfect door panels, headliner, body is South Carolina super solid and the paint is very good, only needing a small touch up around the back of the top where a blister or two are beginning.

It doesn't seem like those cars have really caught on yet. I'm thinking $4,000-$4,500 or so fixed, any other opinions?

[NYJets53]

Get new battery cables and clean all the grounds, everywhere....Did it to mine and the starter works great now....

[Faded Crest]

Originally Posted by NYJets53

Get new battery cables and clean all the grounds, everywhere....Did it to mine and the starter works great now....

Wish I could try it... not my car, though. It would be a $1,800 gamble.