From: The Derfer on
It's happening again.
A new cap helped for a while but since the weather got warmer, I get
coolant overflow out the overflow tank once I turn the car off.
This is a 1970 Cadillac Eldorado (yes, the monster 500 CI motor with
400 HP).
As long as the car's on, it's fine. Turn it off and there's
monstrous gurgling,
fluid surges to the overflow tank and not long after, right out the
overflow hose.
Strangely, I check the car once it cools down (circa 3 hours later)
and the
coolant is all the way to the top of the radiator cap. That'd
ordinarily mean it's
overfilled but I don't think it can be.
Today I tried just turning the car on for 30 minutes (without driving
it) and this
happened.
Suggestions? The radiator is maybe 5 years old, with very few miles
driven on
the car since then. One coolant change (power flush) since then,
perhaps 2-3 years ago.

Thanks in advance to anyone who can help.
From: jim on


The Derfer wrote:

> It's happening again.
> A new cap helped for a while but since the weather got warmer, I get
> coolant overflow out the overflow tank once I turn the car off.
> This is a 1970 Cadillac Eldorado (yes, the monster 500 CI motor with
> 400 HP).
> As long as the car's on, it's fine. Turn it off and there's
> monstrous gurgling,
> fluid surges to the overflow tank and not long after, right out the
> overflow hose.
> Strangely, I check the car once it cools down (circa 3 hours later)
> and the
> coolant is all the way to the top of the radiator cap. That'd
> ordinarily mean it's
> overfilled but I don't think it can be.
> Today I tried just turning the car on for 30 minutes (without driving
> it) and this
> happened.
> Suggestions? The radiator is maybe 5 years old, with very few miles
> driven on
> the car since then. One coolant change (power flush) since then,
> perhaps 2-3 years ago.

How long since a tune-up by someone who knew what they were doing?

The first thing I would check is the vacuum advance in the distributor.
If the advance diaphragm is still good (unlikely if it is original) then
check the thermostat.
Also check the lower radiator.

-jim

From: m6onz5a on
On May 5, 6:51 pm, The Derfer <derf...(a)gmail.com> wrote:
> It's happening again.
> A new cap helped for a while but since the weather got warmer, I get
> coolant overflow out the overflow tank once I turn the car off.
> This is a 1970 Cadillac Eldorado (yes, the monster 500 CI motor with
> 400 HP).
> As long as the car's on, it's fine.   Turn it off and there's
> monstrous gurgling,
> fluid surges to the overflow tank and not long after, right out the
> overflow hose.
> Strangely, I check the car once it cools down (circa 3 hours later)
> and the
> coolant is all the way to the top of the radiator cap.  That'd
> ordinarily mean it's
> overfilled but I don't think it can be.
> Today I tried just turning the car on for 30 minutes (without driving
> it) and this
> happened.
> Suggestions?   The radiator is maybe 5 years old, with very few miles
> driven on
> the car since then.  One coolant change (power flush) since then,
> perhaps 2-3 years ago.
>
> Thanks in advance to anyone who can help.

are you sure you don't have any air in the system?

You can always try a new thermostat, or maybe put a lower temp one in.
From: Kevin Bottorff on
m6onz5a <corvair(a)comcast.net> wrote in news:1b2f6637-eebc-4d40-8f15-
757fdd831156(a)k19g2000yqm.googlegroups.com:

> On May 5, 6:51�pm, The Derfer <derf...(a)gmail.com> wrote:
>> It's happening again.
>> A new cap helped for a while but since the weather got warmer, I get
>> coolant overflow out the overflow tank once I turn the car off.
>> This is a 1970 Cadillac Eldorado (yes, the monster 500 CI motor with
>> 400 HP).
>> As long as the car's on, it's fine. � Turn it off and there's
>> monstrous gurgling,
>> fluid surges to the overflow tank and not long after, right out the
>> overflow hose.
>> Strangely, I check the car once it cools down (circa 3 hours later)
>> and the
>> coolant is all the way to the top of the radiator cap. �That'd
>> ordinarily mean it's
>> overfilled but I don't think it can be.
>> Today I tried just turning the car on for 30 minutes (without driving
>> it) and this
>> happened.
>> Suggestions? � The radiator is maybe 5 years old, with very few miles
>> driven on
>> the car since then. �One coolant change (power flush) since then,
>> perhaps 2-3 years ago.
>>
>> Thanks in advance to anyone who can help.
>
> are you sure you don't have any air in the system?
>
> You can always try a new thermostat, or maybe put a lower temp one in.


how old is the water pump. some of those old beasts would eat the
impellers us so they wouldnt move enough water. KB

--- news://freenews.netfront.net/ - complaints: news(a)netfront.net ---
From: Ashton Crusher on
On Wed, 5 May 2010 15:51:40 -0700 (PDT), The Derfer
<derf109(a)gmail.com> wrote:

>It's happening again.
>A new cap helped for a while but since the weather got warmer, I get
>coolant overflow out the overflow tank once I turn the car off.
>This is a 1970 Cadillac Eldorado (yes, the monster 500 CI motor with
>400 HP).
>As long as the car's on, it's fine. Turn it off and there's
>monstrous gurgling,
>fluid surges to the overflow tank and not long after, right out the
>overflow hose.
>Strangely, I check the car once it cools down (circa 3 hours later)
>and the
>coolant is all the way to the top of the radiator cap. That'd
>ordinarily mean it's
>overfilled but I don't think it can be.
>Today I tried just turning the car on for 30 minutes (without driving
>it) and this
>happened.
>Suggestions? The radiator is maybe 5 years old, with very few miles
>driven on
>the car since then. One coolant change (power flush) since then,
>perhaps 2-3 years ago.
>
>Thanks in advance to anyone who can help.


Sounds like you don't have a high enough concentration of antifreeze.
Do you have an infrared temp gun you can aim at the thermostat housing
to see what temp the coolant is at? The last vehicle I had that did
what yours is doing was cured with a new radiator cap but you say
you've already put one on it. Are you sure you put on the right
pressure rating cap, it probably is supposed to be a 15 pound cap,
maybe you put on a lower pressure cap then that. See if there's a gas
station that has the gizmo that can check your coolant concentration
to see if the ratio of water to antifreeze is at least 50/50.