Against my advice my friend bought this car a month ago. Within weeks it overheated and would not start. The guy he bought it from came got it and "said" he put a new water pump on it.
Now it has started overheating to the point it is spitting steam (smoke?) into the inside as well as outside of the car.
He knows Nothing much about cars and I am trying to figure what it may be that would possibly cause this so at least we can get a clue as to what it will cost to fix.
Any ideas?
Thank you

The radiator likely needs replacing, due to phosphate scale:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-3.html#post235973

Thank you I will pass it on.

Any clue what something like that ruins?
It is a Eldorado 1985.
I am in Maryland in case that makes a difference.



Thank you

The sensor that controls the radiator cooling fans can potentially sustain damaged when servicing certain cooling system components on some models of that engine.

That having been said:
The resulting inadvertent damage could result in less than optimum cooling system performance, I.E.: overheating.

What prior Cadillac engie repair experience did the person have that replaced the water pump?

If a person isn't careful, that particular sensor may have inadvertently become damaged.
That, and some O-rings that haven't moved in years could and should also be suspected of leaking.
Someone, probably not the seller, needs to do a thorough inspection to determine what is really needed.

In the marine world, they call it a survey. It is usually done by people with experience in the area.
With cars, it's just a second opinion.
I sure wish more car-knowin' people could educate the car-not-so-knowin' people before their "car-buying passion" over-rules the "car-buying needs and realities."

Inquire here for your second opinion.