3 radiators in 1978 Eldorado?

[Tornike]

Hello there,
having started a restoration on my '78 Cadillac Eldorado Biarritz, I'm coming along some mystery 'surprises'. For instance, the 4 wood logs literally tacked inside the rear bumper (exposed after I removed the fillers).
I got this car off an auction from the MOPAR collectioner in SD, who had recently passed away. He had this and 4-5 corvettes from the GM.

I discovered there are 3 RADIATORS under the hood. Two normal ones and than there is a third small one way out front between the oil radiator and a grille. It is connected to the main radiator with a thicker metal + rubber hose that looks like the ones usually coming out from the AC, but this one is used to connect the two radiators. Attaching pictures.

I ran the car and it sounds fine, other than squeaking noise coming out of the belt until it stops after few minutes (I will have a separate question about that). I drove it really briefly and rolls fine too (love the suspension, it's just a magic).

What could this 3rd radiator be for? The main radiator could be bad? Why is it connected to the main one? I don't get any light in the dashboard, although I have not stressed it enough other than running it for 10 minutes in 90 degree hot day.

I'm pretty sure the car was used for hauling the RV occasionally, as I there is Kelsey Hayes trailer braking module installed under the steering wheel. And I also found a trailer power outlet hidden behind the rear bumper.

If the radiator could be bad, could this tiny one do a trick? I'm thinking why the owner would not replace damaged radiator itself instead of drilling a third one? Suggestions appreciated.

[bcroe]

Sometimes a trans fluid cooler is added, to increase cooling over stock.
Bruce Roe

[Mike Josephic CLC #3877]

With the "reinforcements" added to the rear bumper
plus the transmission oil cooler (I agree with Bruce)
it sounds like this car was rigged for towing a trailer.

If you look, you will likely see signs of holes where
a rear hitch was previously bolted to the frame.

Mike

[Tornike]

Right, everything coming together now and making sense. Very helpful. Mike, I would never have thought those wood logs would carry importance. I appreciate your insight, Bruce!
Would you recommend removing the trailer braking module? I hate the way it looks with its wires sticking out in such a nice interior.

I suppose I leave the third radiator as it is then, right?

I'm half happy, as I could enjoy having all these mods myself, but on the other hand this will most certainly affect the car value negatively.

[The Tassie Devil(le)]

Definitely a transmission cooler.

A lot of auto makers recommend that an external cooler be added to the factory cooler when towing.

Lowering the transmission fluid by 10 degrees really extends the fluid life.   There was a formula, but I cannot remember it.

Bruce.

PS.   That mesh in the front is indicative of vehicle useage in some very unfriendly terrain.

[Tornike]

Definitely a transmission cooler.

A lot of auto makers recommend that an external cooler be added to the factory cooler when towing.

Lowering the transmission fluid by 10 degrees really extends the fluid life.   There was a formula, but I cannot remember it.

Bruce.

PS.   That mesh in the front is indicative of vehicle useage in some very unfriendly terrain.

Won't be surprised, as it was kept and driven at a South Dakota ranch so far off the road that I had hard time finding the truck driver who could agree to deliver it just 900 miles south.

Do I need to look into particular areas of car to determine any risky parts that usually go bad on country roads?
I know that air shocks and muffler have been replaced in 2012. Car has been sitting since then.

[The Tassie Devil(le)]

Ah ha.   Probably driven across the prairie lands and the mesh is there to keep the flying critters (Locusts and the like) from blocking up the radiator fins.

The bugs at nighttime, especially the 100 Mph Bugs can really block up orifices, and bug splatter on the windscreen is also really hard to clean off.

Bruce.

[35-709]

You can remove the brake controller if you aren't going to be pulling a trailer but I would leave the tranny cooler since it is already there.  Unless you are in Alaska, you really can't cool an automatic transmission too much and generally the cooler the better.  You might want to replace the hoses to and from the tranny cooler though just as a precaution because of age. 

["Cadillac Kid" Greg Surfas 15364]

For what it is worth Tornike, that is just about the smallest (coolant) radiator I have seen on an Eldorado.  It is definitely one that you would want to use in anything but the coldest of climates, even with the 425 motor.  O a, speaking of course of the main radiator.  I would have to believe they installed the transmission cooler because the replacement radiator they used definitely did not have the capacity to cool the engine and the transmission.  I would seriously give some thought to installing the correct radiator before taking any long trips.
Greg Surfas

[Tornike]

Would you fellows agree with Greg? That a main coolant radiator is small?

I can’t tell it myself as to my eye the other radiators from the reference images seem similar in size.

First two images are of my car. The rest are of other ‘78 Eldorados

I live in Missouri

[The Tassie Devil(le)]

Nothing wrong with the capacity of the original Radiator, as Cadillac spent millions of dollars on maintaining the design, and the design had to cover vehicles that were used in the hottest climates, to the coldest climates, and I have never heard of them giving strife.

Bruce.

["Cadillac Kid" Greg Surfas 15364]

From the pictures it appears as if only the last two have original type, Brass/Copper radiators.  The others appear to have replacement type single row Plastic/Aluminum devices.  Eldos do need all the radiator they came with and I personally have never heard of anyone that has been happy with one of the plastic ones.
Greg Surfas

[67_Eldo]

Sometimes a trans fluid cooler is added, to increase cooling over stock.

I agree with Bruce: Transmission cooler.
However, my 1967 Eldorado also sports a tiny power-steering-fluid cooler that is mounted on the driver's-side inner fender. I don't see one on your car.

Does it look like your power-steering lines are running off to a cooler somewhere?

[TJ Hopland]

I believe most of the 70's Cads the power steering cooler was a loop of hard metal line hanging down below the radiator.

[The Tassie Devil(le)]

Yes, these are only required in LHD cars where the pipes from the Pump to the Steering Box are really short.

In the same car in RHD form, the line is sufficiently long enough to not require the separate cooling device.

The fluid gets hot when tooling around town and negotiating parking spots.

Bruce.

[35-709]

I believe most of the 70's Cads the power steering cooler was a loop of hard metal line hanging down below the radiator.

Right, that is the way my '73 is.  My '66 had a small cooler for the PS too but as TJ says that was later changed.