Burnt out wiring in a '72 Eldorado WARNING

[The Tassie Devil(le)]

G'day all,

I had a possible disaster happen to me last week, and it took me this long to report it as I waited till now to have the full set of pictures to post as a warning to all.

And yes, I apologise for not taking a picture of the actual burnt out loom before I pulled it from the car, but I was in a bit of a hurry to get the car going as I was a hundred miles from home, going in the opposite direction.

It all happened when we stopped for lunch, the outside temperature was over 40C, and we had just had a lovely snack for lunch, when a lady who was looking and admiring the car as I attempted to start it yelled that there was smoke coming out from under the hood, then I too saw it.   Boy, it was a black cloud, coming from the left rear corner.

Without hesitation, I turned off the ignition, popped the hood and saw that the smoke was coming from the right rear corner of the engine.   And I then twisted off the negative terminal from the battery post to isolate the electrics.   Thankfully, my car has the clamp-on posts, and not the factory bolt-on posts.

Now for the fault.

The loom from the Starter Solenoid to the firewall had shorted out on the retaining bracket that was on the bottom bellhousing bolt and had burnt the insulation from the Resistance terminal of the Solenoid, and then the main Fusible Link burnt out, thus stopping any further shorting out.

I had to wait till things cooled down a bit so I could fabricate a fix, and I cut a piece of hose from the fresh air feed to the ALC and split it so I could re-insulate the Resistor wire feed, which is 12 volts whilst cranking, and twisted the fusible link back together after easily removing the burnt ends of its' own insulation.

Using more of the split rubber hose, and some electrical tape that I managed to purchase at the shop, I fashioned a suitable repair, and continued on our journey.   I had an emergency tool kit, but Bronwyn had to supply the nail scissors to allow the splitting of the hose.

Picture No. P1300049 shows the emergency repairs after I got home and pulled out the wiring and Starter Motor.   Note the melted plastic wrap that I had put around the loom to protect it had melted.
Picture No. P1300064 shows the fused fusible link at the top, Coil wire centre and another fusible link about to blow.
Picture No. 1300050 shows the rebuilt loom about to go back in.
Pictures 1300055 and P1300062 show the offending steel bracket, but this time holding the re-insulated loom, and how close it is to the exhaust pipe.

I thought I had sufficiently protected the loom, but sadly, not.

It would pay for all owners of Eldorados with the Front Wheel Drive engines to have a quick look at this area in your vehicles, as I would hate to see it happening to anyone else.   There is a lot of heat down there, and not just on hot days.

Bruce.

[wrench]

Thanks for the warning.

It is a tight area and exposed to high temps and worse if the exhaust joint there is leaking.

I will give the area some more attention the next time I am in there.

[bcroe]

There you are again, running your power harness down to the starter
terminal subjects it to heat, oil/water, and vibration.  Following the OEM
design on my 62, I route my battery cables to a safe clean terminal high
on the fender, then continue on to the starter.  The only other wire to the
starter is to activate the solenoid. 

The rest of the car wiring connects up on that nice clean, dry, vibration
free terminal on the fender.  Note the fusible links.  Bruce Roe

[The Tassie Devil(le)]

....... I route my battery cables to a safe clean terminal high on the fender, then continue on to the starter.  The only other wire to the starter is to activate the solenoid.    The rest of the car wiring connects up on that nice clean, dry, vibration free terminal on the fender.  Note the fusible links.  Bruce Roe

G'day Bruce,

I had thought of that, and looking at the loom, I wondered why Cadillac engineers didn't do that in the first place for all cars.   But as the car has survived 48 years without trouble, I just rebuilt what was there.

I am going to keep an eye on it, and if necessary, I am going to go that route, as I only need the wire going to the Solenoid, as my car has been converted to HEI, and therefore I have full 12 Volts from the ignition to the coil, bypassing the Resistance feed.

Bruce.

PS.   As I am not into Judging, it isn't going to hurt whatever I do.

[Roger Zimmermann]

Well, Bruce, you had some luck in that situation. Better a repair almost on the side of the road than to call the firemen. Don't know if the situation is similar to the RWD '72; I will also have a look. In your case, there are probably more MY which can be affected.

["Cadillac Kid" Greg Surfas 15364]

G'day
Seemingly a common problem with the Eldos.  My '72 toasted itself just about like that and at the time I as able to buy the starter harness.  I bought 4 and I still have one left, so you and the saltys are not alone down there Mate.
Greg Surfas

[hornetball]

Note to self, buy small tookit and fire extinguisher for Janice's Eldo.

The car had that harness repaired prior to my ownership.  Now I know why.  Will add to my inspection routine.

The positive battery cable is also heavily exposed to exhaust manifold radiation.  Cadillac encased the cable in heat protection from the factory, but this deteriorates.  I found substitute heat protection conduit on Rock Auto (https://www.rockauto.com/en/moreinfo.php?pk=926398&jsn=3078) and refreshed it on Janice's Eldo.  I'll bet something similar would be effective for the starter harness as well.

[fishnjim]

I think it's a more general safety issue than just this one model, it's old wiring.
I keep harping on this, but here's another example.  One guy on here lost his whole car a few years ago.   
The wiring just won't last forever!   Prevention is the key.
When it gets around 30ish years old, it's time to change.   At least start inspections.  So anything before 1990-2000 is on deck.   
The modern wiring insulation is much better than what they had back in the 50, 60, early 70's.   But wire insulation still uses the cheapest grade of PVC.   Make sure you use proper automotive grade wire.   There's a SAE number(s) for it.   What's on the shelf at the parts store and cheap may not be.
I rewired my engine compartment, while I had the motor out, after the horn self ignited from some dodgy PO repairs and desintegration of a paper horn insulator.   So you don't always know what hides under the tape, factory or not.   I took pictures of more bad factory wires I found under the tape, invisible from outside and posted with the '58 owners.   
What happens is the insulation cracks then the wire is exposed to corrosion.   Corrosion causes resistance, resistance cause heat, and eventually it exceeds the ignition temp and it's burning.
There are several places selling complete harnesses, and auto electric places if you can't DIY.
ps: I used to make additives for PVC since '79.

[Mike Baillargeon #15848]

"Boy, it was a black cloud, coming from the left rear corner."

"Without hesitation, I turned off the ignition, popped the hood and saw that the smoke was coming from the right rear corner of the engine.   And I then twisted off the negative terminal from the battery post to isolate the electrics.   Thankfully, my car has the clamp-on posts, and not the factory bolt-on posts."



Wow Bruce that was some quick reacting on your part!....

You never know what is under that hood when it's smoking....You hope its just a heater hose and you also hope it's not the carb and intake completely engulfed in flames...

Your action probably saved the car....you could easily see the burning harness getting the firewall & dash involved...then it's all over but the crying....

Mike

[The Tassie Devil(le)]

You never know what is under that hood when it's smoking....You hope its just a heater hose and you also hope it's not the carb and intake completely engulfed in flames... Mike

Before I opened the hood, I was very wary of the smoke coming from a carburettor/fuel fire, and stood low and away from the front, just in case the sudden burst of incoming air fueled the fire more.

Have seen it where people get caught in the flash of bursting flames, and the result is not good.

Bruce.

PS.   I was parked next to a petrol outlet, and there were sufficient fire extinguishers around just in case.

[Cadman-iac]

PS.   I was parked next to a petrol outlet

That much more to go boom too!!!

I'm glad you got it out and saved your car.

[SixDucks]

Hi Bruce,

  In the past I've used a product from Taylor called Fire sleeve. It solved my issues with battery cables and the starter harnesses on my drag car. I recently purchased additional sleeve for my dually and will also be installing this to one of my Cadillacs as well. When I had my starter rebuilt I found less than ideal wiring to the starter when doing the repair.
Hope this helps anyone else with fire prevention.

Terry

[Scot Minesinger]

I have suffered shorts in Eldorados, and now thanks to this post I know where to look.  Thanks!  And I like the idea of bring all the power wires up from the starter to a much nicer safer location on the inner fender. 

[Big Fins]

Looks like I know how I'll be spending one of my vacation days. 

Time to search for and secure the needed parts. I always hated these side mount batteries and being as it's 6 years old, I have a good excuse to change it out to a top mount with either quick disconnects or a marine style battery switch. 

[The Tassie Devil(le)]

I would be going for the Marine Style quick disconnect as a minimum with the side post battery, but thankfully, we have never had the Side-mounts available in Australia.

The only Bolt-on ones are the super expensive Deep Cycle Batteries, and I have just acquired a couple of these from a Invalid cart, and might consider installing it into my Eldorado one day.

Bruce.

[dochawk]

I have suffered shorts in Eldorados, and now thanks to this post I know where to look. 

Mine was *relying* on a short when I bought it.

Some yahoo had attached the starter wire to the wrong post (which seems to have no purpose other than to enable this mistake!).   

But another wire had been left attached to one post or the other, which lay across the other, connecting the juice to the other, until one day it just wouldn't start . . .  it took a *huge* amount of time to track that one down . . .

(and that's not the weirdest rechecking they did to this car . . .)


hawk