Overheated Cadillac DeVille

[DeVille]

have a 1987 DeVille w/4100 block and it ran hot. I have since changed the water pump and noticed that there is water seeping from right below the carborator. I do not believe that the water pump created the problem. Is there anyone that knows what might have created this problem, and what has to be done to repair the leak?

[ctesla]

I do not believe the water pump created this problem either; however, the antifreeze is "puddled" on the manifold under the carb...
where is it from? is there just a hose connection that is loose maybe?
or is there a PVS (ported vacuum switch) that has a cracked fitting?
or maybe the thermostat housing (when it overheated) cracked, or broke a seam or seal?
I would be more than happy to assist (and I think others would be too), however, you need to help us, help you...
explain the vehicle, mileage, what ocurred during overheating (and how long, 10 minutes up past H, or needle rose to H and you shut it off),
explain in detail (if you can) where it "looks" like the antifreeze could be coming from under the carb (we can't be there to see it); was the water pump leaking after over heat??? if so, maybe the puddle on the manifold is just spray from the water pump under the hood--- is there any antifreeze ON the underside of the hood?

I do not think no one answered your question for not wanting to help, but because they (like me) are unsure where the antifreeze came from.
plus it does sometimes take enough people to see the post prior to responding.

[ctesla]

Originally Posted by DeVille

have a 1987 DeVille w/4100 block and it ran hot. I have since changed the water pump and noticed that there is water seeping from right below the carborator. I do not believe that the water pump created the problem. Is there anyone that knows what might have created this problem, and what has to be done to repair the leak?

when you say "seeping";
is it coming right from where the carb bolts to manifold?
if so, loosen the carb's four bolts just enough to lift the carb up a little and break the seal with the engine...
did the antifreeze pour from here?
if so, you have water up through the runners of your intake manifold, and that means in your valves, and on top of the pistons as well;
if this is the case, the overheating was critical:
time to pull heads.
sorry.

[DeVille]

Thank you all so much for responding to my questions. The car overheated for about 15 min. The water pump was not leaking. I am going to take a closer look at the parts that you suggested and tell you what I see. When I replaced the water pump I allowed the engine to run about 10 min., until I saw the antifreeze leaking from underneath the car. Then I turned the moter off so that I could investigate the leak. It was then that I noticed antifreeze squirting from close to the carb, and the thermostat housing. But it looked to me at the time that it was squirting from where there might be a gasket on the head. Then I removed the radiator cap and refilled the radiator and started the engine w/out replacing the radiator cap. After about 5 or 10 minutes, antifreeze started gushing from the radiator. I have had cars running in the past w/out the cap on before and never have I seen fluid gush out like that. Could there be something clogged, or what should my next step be?

[DeVille]

The engine has 33,000 original miles on it

[Ryan066]

Originally Posted by DeVille

The engine has 33,000 original miles on it

prolly a plugged rad, try draining a water hose through it to see if water comes out the bottom.

after further reading .. it sounds like to me the rad got clogged.. stopped flow of coolant... overheat... and now the HG is blown and coolant is leaking around the head... and prolly a warped head now.

is the oil milky colored?

[DeVille]

do you think a new head or just have the existing one machined?

[ctesla]

Originally Posted by DeVille

do you think a new head or just have the existing one machined?

as ryan suggested, it might be just a clogged rad.
but it could be heads... 33K original, might not be heads, if this has sat or had very limited use:
1987 form 33K= 1830+ miles in ONE YEAR! most cars do that in a month!
it could be the radiator core has slowly built up a deposit to clog the hoses and coolant flow.
check that first, and also pull the thermostat (if you are not sure if that spray was coming from it), you can put in a new t-stat, and take a look inside to see what it looks like. if their is large deposits (or sludge, like someone used BarDahl or AlumaSeal stop leak products, it might just be clogging the heater core) stopping flow and creating an overpressure.
until you isolate problem, use water:
cheaper and environmentally friendly.

[Ryan066]

Originally Posted by DeVille

do you think a new head or just have the existing one machined?

if the head is warped they can be machined, yes.

but i would do alot more investigation before ripping the head(s) off. do what like ctesla said.

an engine compression and pressure test of the cooling system would prolly do you good.

[DeVille]

I took a picture of the leak and it is in the gallery

[DeVille]

Heres a link to the photo

[DeVille]

Sorry link didn't work

[DeVille]

Where would be the best place to find a new head for this car?

[creeker]

Originally Posted by DeVille

Where would be the best place to find a new head for this car?

I used to have a 1992 caddy with a 4.9, like the 4.1 it has alum. block and cast cylinder sleeves and cast head, after any cooling system work you have to put in these felt material tablets (a g.m. product) in the rad. they break up and seek out and fill any voids between cast iron and aluminum. kinda like a crack filler.