Help- Leaking antifreez from the overflow resevoir

My son has a 97 Cavalier, we have had the therostat and a couple of
other connections fixed. Now it seems to be leaking from the
resevoir, not all the time but to often to not fix it. Any Idea what
is causing this, Not sure if its the cap resevoir itself. Why would
there be that much presure??

On Aug 27, 2:31 pm, Scott Mezquita --Buggzy >
wrote:
> My son has a 97 Cavalier, we have had the therostat and a couple of
> other connections fixed. Now it seems to be leaking from the
> resevoir, not all the time but to often to not fix it. Any Idea what
> is causing this, Not sure if its the cap resevoir itself. Why would
> there be that much presure??

My guess is the mechanic didn't purge the cooling system of air after
working on the cooling system. Take it back to the mechanic that did
the work and have him fix it.

"Scott Mezquita --Buggzy" > wrote in message
ups.com...
> My son has a 97 Cavalier, we have had the therostat and a couple of
> other connections fixed. Now it seems to be leaking from the
> resevoir, not all the time but to often to not fix it. Any Idea what
> is causing this, Not sure if its the cap resevoir itself. Why would
> there be that much presure??

Were the repairs made because of leakages, or something else?

Dont know what engine you have in that car, but several of the V6 engines
have some typical weaknesses, some of which could result in communication
between the combustion chambers and the cooling system...If you have a
leakage
of hot exhaust gas into the water jackets, of course you may see overheating
and coolant being pressured out of the reservoir.

Sorry to bring up this bit of pessimism...May be something a lot simpler and
easier to resolve.

On Aug 27, 2:31 pm, Scott Mezquita --Buggzy >
wrote:
> My son has a 97 Cavalier, we have had the therostat and a couple of
> other connections fixed. Now it seems to be leaking from the
> resevoir, not all the time but to often to not fix it. Any Idea what
> is causing this, Not sure if its the cap resevoir itself. Why would
> there be that much presure??

I had this exact issue on my F**d pickup truck, the problem was two
connections reversed on the neck of the radiator (bypass hose for
heater was switched with the overflow hose causing the system not to
pressurize; it would puke when hot.)

Other possibilities include a weak radiator cap, a crack in the
overflow bottle, or worst, a blown head gasket allowing the engine to
push combustion gases into the cooling system.

nate

On 8/27/07 1:31 PM, in article
, "Scott Mezquita
--Buggzy" > wrote:

> My son has a 97 Cavalier, we have had the therostat and a couple of
> other connections fixed. Now it seems to be leaking from the
> resevoir, not all the time but to often to not fix it. Any Idea what
> is causing this, Not sure if its the cap resevoir itself. Why would
> there be that much presure??
>

There are a few cars (VW for one) that maintain a pressurized overflow tank,
but most others do not maintain any sort of pressure in the overflow tank.
In fact, if you look closely, you will probably find a hole near the top of
the tank to allow excess overflow to simply pour out.

If the radiator cap is bad (not holding pressure), then more coolant will
push out into the overflow than should. Get the cap checked.

On some cars, an air bubble in the system can cause spectacular boiling out
into the overflow. Since you've just replaced the thermostat and some
"other" things, air was probably introduced into the system. Check to make
sure the system was properly "burped" of air.

Other possibilities are ugly and expensive, like blown head gasket, cracked
head, etc. You really want to hope its just a radiator cap or air bubble.

On Aug 29, 7:30 pm, E Meyer > wrote:
> On 8/27/07 1:31 PM, in article
> om, "Scott Mezquita
>
> --Buggzy" > wrote:
> > My son has a 97 Cavalier, we have had the therostat and a couple of
> > other connections fixed. Now it seems to be leaking from the
> > resevoir, not all the time but to often to not fix it. Any Idea what
> > is causing this, Not sure if its the cap resevoir itself. Why would
> > there be that much presure??
>
> There are a few cars (VW for one) that maintain a pressurized overflow tank,
> but most others do not maintain any sort of pressure in the overflow tank.
> In fact, if you look closely, you will probably find a hole near the top of
> the tank to allow excess overflow to simply pour out.
>
> If the radiator cap is bad (not holding pressure), then more coolant will
> push out into the overflow than should. Get the cap checked.
>
> On some cars, an air bubble in the system can cause spectacular boiling out
> into the overflow. Since you've just replaced the thermostat and some
> "other" things, air was probably introduced into the system. Check to make
> sure the system was properly "burped" of air.
>
> Other possibilities are ugly and expensive, like blown head gasket, cracked
> head, etc. You really want to hope its just a radiator cap or air bubble.

The '97 Cavalier uses a pressurized bottle, very similar to the VW.

On Aug 30, 11:05 am, wrote:
> On Aug 29, 7:30 pm, E Meyer > wrote:
>
>
>
>
>
> > On 8/27/07 1:31 PM, in article
> > om, "Scott Mezquita
>
> > --Buggzy" > wrote:
> > > My son has a 97 Cavalier, we have had the therostat and a couple of
> > > other connections fixed. Now it seems to be leaking from the
> > > resevoir, not all the time but to often to not fix it. Any Idea what
> > > is causing this, Not sure if its the cap resevoir itself. Why would
> > > there be that much presure??
>
> > There are a few cars (VW for one) that maintain a pressurized overflow tank,
> > but most others do not maintain any sort of pressure in the overflow tank.
> > In fact, if you look closely, you will probably find a hole near the top of
> > the tank to allow excess overflow to simply pour out.
>
> > If the radiator cap is bad (not holding pressure), then more coolant will
> > push out into the overflow than should. Get the cap checked.
>
> > On some cars, an air bubble in the system can cause spectacular boiling out
> > into the overflow. Since you've just replaced the thermostat and some
> > "other" things, air was probably introduced into the system. Check to make
> > sure the system was properly "burped" of air.
>
> > Other possibilities are ugly and expensive, like blown head gasket, cracked
> > head, etc. You really want to hope its just a radiator cap or air bubble.
>
> The '97 Cavalier uses a pressurized bottle, very similar to the VW.- Hide quoted text -
>
> - Show quoted text -

Aren't most cars pressurized in the bottle now? No caps on
radiators. Only on bottles. No?

On Aug 30, 3:22 pm, wrote:
> On Aug 30, 11:05 am, wrote:
>
>
>
>
>
> > On Aug 29, 7:30 pm, E Meyer > wrote:
>
> > > On 8/27/07 1:31 PM, in article
> > > om, "Scott Mezquita
>
> > > --Buggzy" > wrote:
> > > > My son has a 97 Cavalier, we have had the therostat and a couple of
> > > > other connections fixed. Now it seems to be leaking from the
> > > > resevoir, not all the time but to often to not fix it. Any Idea what
> > > > is causing this, Not sure if its the cap resevoir itself. Why would
> > > > there be that much presure??
>
> > > There are a few cars (VW for one) that maintain a pressurized overflow tank,
> > > but most others do not maintain any sort of pressure in the overflow tank.
> > > In fact, if you look closely, you will probably find a hole near the top of
> > > the tank to allow excess overflow to simply pour out.
>
> > > If the radiator cap is bad (not holding pressure), then more coolant will
> > > push out into the overflow than should. Get the cap checked.
>
> > > On some cars, an air bubble in the system can cause spectacular boiling out
> > > into the overflow. Since you've just replaced the thermostat and some
> > > "other" things, air was probably introduced into the system. Check to make
> > > sure the system was properly "burped" of air.
>
> > > Other possibilities are ugly and expensive, like blown head gasket, cracked
> > > head, etc. You really want to hope its just a radiator cap or air bubble.
>
> > The '97 Cavalier uses a pressurized bottle, very similar to the VW.- Hide quoted text -
>
> > - Show quoted text -
>
> Aren't most cars pressurized in the bottle now? No caps on
> radiators. Only on bottles. No?- Hide quoted text -
>
> - Show quoted text -

My son has a 2000 Malibu with the 3.1 liter V6. He had this happen on
a trip out west two years ago. After replacing thermostat, water pump
and flushing the system, the problem was determined to be a bad
recovery tank cap. The tank is pressurized during engine operation and
is in fact the only place coolant can be added. The radiator itself
has no cap.