Replace coolant after replacing a heater core?

I read this in the Bentley manual regarding replacing the heater core

"Always replace coolant after removal/replacement"

I cannot think why this would be necessary. I replaced the coolant
just a few months before the heater core change so I am not thrilled to
do this again. I have been using G12 coolant for several years.. does
this have any bearing on the issure?

My heater core failed quickly.. I only drove for about 10 seconds after
the leak started... then I bypassed the heater core for a few days but
only drove the car about 10 miles during the bypass.

Does anyone know the technical reason for replacing the coolant with
the heater core job? Of course the reasons not to are 1. cost and 2.
environmental impact that my not be necessary. 3. its freaking cold
outside.!


thanks!

Mark

"Mark" > wrote

>I read this in the Bentley manual regarding replacing the heater core
>
> "Always replace coolant after removal/replacement"

That can be taken two ways. "Replace" *lost* coolant from the loss of
coolant that was in the core and what little may have spilled out.

If it said, "completely replace coolant" it would be different. Obviously,
any coolant lost HAS to be replaced and it is impossible to do the job
without having to replace some coolant even if it is pouring (figure of
speech) coolant from the old core into the tank (not saying to do this).

It IS an opportunity though for old (not yours) coolant to be completely
replaced while a person is working on it. If I did this I would backflush
the whole system. You can buy a self back flush kit (not as good as the
commercial stations) that works very well for 5 or 6 dollars at discount
parts stores.

You do not need to completely change the coolant if clean. Just replace
coolant lost obviously. That is what they meant, imo.

Harry



>
> I cannot think why this would be necessary. I replaced the coolant
> just a few months before the heater core change so I am not thrilled to
> do this again. I have been using G12 coolant for several years.. does
> this have any bearing on the issure?
>
> My heater core failed quickly.. I only drove for about 10 seconds after
> the leak started... then I bypassed the heater core for a few days but
> only drove the car about 10 miles during the bypass.
>
> Does anyone know the technical reason for replacing the coolant with
> the heater core job? Of course the reasons not to are 1. cost and 2.
> environmental impact that my not be necessary. 3. its freaking cold
> outside.!
>
>
> thanks!
>
> Mark
>

Harry wrote:
> "Mark" > wrote
>
>>I read this in the Bentley manual regarding replacing the heater core
>>
>> "Always replace coolant after removal/replacement"
>
> That can be taken two ways. "Replace" *lost* coolant from the loss of
> coolant that was in the core and what little may have spilled out.
>
> If it said, "completely replace coolant" it would be different.
> Obviously, any coolant lost HAS to be replaced and it is impossible
> to do the job without having to replace some coolant even if it is
> pouring (figure of speech) coolant from the old core into the tank
> (not saying to do this).
> It IS an opportunity though for old (not yours) coolant to be
> completely replaced while a person is working on it. If I did this I
> would backflush the whole system. You can buy a self back flush kit
> (not as good as the commercial stations) that works very well for 5
> or 6 dollars at discount parts stores.
>
> You do not need to completely change the coolant if clean. Just
> replace coolant lost obviously. That is what they meant, imo.
>
> Harry
>
>
>
>>
>> I cannot think why this would be necessary. I replaced the coolant
>> just a few months before the heater core change so I am not thrilled
>> to do this again. I have been using G12 coolant for several years..
>> does this have any bearing on the issure?
>>
>> My heater core failed quickly.. I only drove for about 10 seconds
>> after the leak started... then I bypassed the heater core for a few
>> days but only drove the car about 10 miles during the bypass.
>>
>> Does anyone know the technical reason for replacing the coolant with
>> the heater core job? Of course the reasons not to are 1. cost and 2.
>> environmental impact that my not be necessary. 3. its freaking cold
>> outside.!
>>
>>
>> thanks!
>>
>> Mark

In addition I might suspect that if the core went, who knows what might
have gotten into the coolant and now resting in the radiator. A flush and
refill with fresh, is what I would do.

--
Joseph Meehan

Dia duit

Mark wrote:

> Does anyone know the technical reason for replacing the coolant with
> the heater core job? Of course the reasons not to are 1. cost and 2.
> environmental impact that my not be necessary. 3. its freaking cold
> outside.!

I think I have read somewhere in the VW documentation, that the coolant
has additives which form some sort of protective layer in order to
inhibit the corrosion. Apparently, the fresh coolant does it much
better as the old "used" coolant.

On the other hand, if you changed the heater core, you probably flushed
some significant amount of coolant anyway, and then topped it up
(hopefully you didn't filled the old one + some water).

In general, if I was you, I wouldn't do anything. Or just buy one
bottle of G12+ concentrate (its 1.5 liters and maybe some $10 (or you
are being ripped)), suck some of the coolant out and the top it up just
with that concentrate. It will not significantly impact the freezing
resistance of the mix and will get you some fresh additives floating
around

That's an interesting thought... that only new G12 coolant has the
ability to 'treat' a fresh heater core. Can anyone verify this theory?

I mixed G12 coolant 50/50 with distilled water and added that to the
cooling system after the restart. No, I did not pay more than $10, I
paid a little more than $8 on germanautoparts.com.


wrote:
> Mark wrote:
>
> > Does anyone know the technical reason for replacing the coolant with
> > the heater core job? Of course the reasons not to are 1. cost and 2.
> > environmental impact that my not be necessary. 3. its freaking cold
> > outside.!
>
> I think I have read somewhere in the VW documentation, that the coolant
> has additives which form some sort of protective layer in order to
> inhibit the corrosion. Apparently, the fresh coolant does it much
> better as the old "used" coolant.
>
> On the other hand, if you changed the heater core, you probably flushed
> some significant amount of coolant anyway, and then topped it up
> (hopefully you didn't filled the old one + some water).
>
> In general, if I was you, I wouldn't do anything. Or just buy one
> bottle of G12+ concentrate (its 1.5 liters and maybe some $10 (or you
> are being ripped)), suck some of the coolant out and the top it up just
> with that concentrate. It will not significantly impact the freezing
> resistance of the mix and will get you some fresh additives floating
> around

"only new G12 coolant has the ability to 'treat' a fresh heater core"

I wouldn't go that far. But, chemically speaking, old coolant has lost
(chemically converted) a lot of its corrosion-protecting components
over time. So new coolant will protect better than old.

Theoreticaly, Its preventative maintenance. Since the heater core rotted out
, the coolant failed to prevent corrosion, and needs to be replaced. The
coolant could be contaminated, which could be due to numerous reasons,
including , Its just old, Improper cleaning of parts during manufacture,
Sand from the engine block casting inside the water jacket, or something
"installed" in the water jacket during assembly. Also there's head gasket
sealer, silicone, hylomar, and others. The owner added something to it.
including but not limited to the following; new freeze plugs, sealers , the
wrong coolant , old rags, additives, cleaners, rust inhibitors, eggs, gasket
sealer, river water, body fluids from the camping trip, oatmeal, old rusting
antuifreeze he found in the garage in an open pan from 3 years ago, or
anything else a stupid owner might put in there to prevent replacing the
heater core,or radiator, to save a buck now , in exchange for spending many
more later. A previous bad radiator rotted out. Or the heater core rotting
out, allowing metal particles into it. or antifreeze sitting around in an
open pan waiting to be put back in,during its replacement, Don't forget
the ****ed of Shop manager or mechanic does something to it, because the
owner complained about the cost. Or somebody puts something in it. or
something falls in it. Picking up road dirt or oil or grease running down
the engine and subframe before getting to the pan, during its removal. Its
cheaper to replace the coolant then to send it to a lab to decide if its
usable or not. or filter the crap out of it somehow, or decide if it will
damage the engine or not. So thats why its replaced.
> wrote in message
oups.com...
> "only new G12 coolant has the ability to 'treat' a fresh heater core"
>
> I wouldn't go that far. But, chemically speaking, old coolant has lost
> (chemically converted) a lot of its corrosion-protecting components
> over time. So new coolant will protect better than old.
>

Treating means,after you get past the marketing hype, that the coolant
touched the metal .That is all. Therefore its working, as the manufacturer
of the antifreeze and VW agreed it should, because its brand new , or has
been replaced, as the Manufacturer of the Bentley manual and VW agreed it
should.
> wrote in message
oups.com...
> "only new G12 coolant has the ability to 'treat' a fresh heater core"
>
> I wouldn't go that far. But, chemically speaking, old coolant has lost
> (chemically converted) a lot of its corrosion-protecting components
> over time. So new coolant will protect better than old.
>

I have to top post this. Good post. Its ironic how some people do
half-assed jobs and then congratulate themselves on the net. My hat
off to you for trying to make a difference...



In article >,
none2u > wrote:
>Theoreticaly, Its preventative maintenance. Since the heater core rotted out
>, the coolant failed to prevent corrosion, and needs to be replaced. The
>coolant could be contaminated, which could be due to numerous reasons,
>including , Its just old, Improper cleaning of parts during manufacture,
>Sand from the engine block casting inside the water jacket, or something
>"installed" in the water jacket during assembly. Also there's head gasket
>sealer, silicone, hylomar, and others. The owner added something to it.
>including but not limited to the following; new freeze plugs, sealers , the
>wrong coolant , old rags, additives, cleaners, rust inhibitors, eggs, gasket
>sealer, river water, body fluids from the camping trip, oatmeal, old rusting
>antuifreeze he found in the garage in an open pan from 3 years ago, or
>anything else a stupid owner might put in there to prevent replacing the
>heater core,or radiator, to save a buck now , in exchange for spending many
>more later. A previous bad radiator rotted out. Or the heater core rotting
>out, allowing metal particles into it. or antifreeze sitting around in an
>open pan waiting to be put back in,during its replacement, Don't forget
>the ****ed of Shop manager or mechanic does something to it, because the
>owner complained about the cost. Or somebody puts something in it. or
>something falls in it. Picking up road dirt or oil or grease running down
>the engine and subframe before getting to the pan, during its removal. Its
>cheaper to replace the coolant then to send it to a lab to decide if its
>usable or not. or filter the crap out of it somehow, or decide if it will
>damage the engine or not. So thats why its replaced.
> wrote in message
roups.com...
>> "only new G12 coolant has the ability to 'treat' a fresh heater core"
>>
>> I wouldn't go that far. But, chemically speaking, old coolant has lost
>> (chemically converted) a lot of its corrosion-protecting components
>> over time. So new coolant will protect better than old.
>>
>
>


--
Jeeps and dubs and everything's nice...

(Peter Parker) writes:

>In article >,
>none2u > wrote:
>>Theoreticaly, Its preventative maintenance. Since the heater core
>>rotted out, the coolant failed to prevent corrosion, and needs to
>>be replaced.

[snip]

>I have to top post this. Good post.

You don't have to top-post. Ever.

>Its ironic how some people do
>half-assed jobs and then congratulate themselves on the net. My hat
>off to you for trying to make a difference...

The assumption is that the heater core failed due to corrosion. That
is of course *seldom* the case in the 10+ million VW that need the
core change. In those, it's because the seal of the ends of the core
has failed or is likely to fail due to a design flaw.
--
/"\ Bernd Felsche - Innovative Reckoning, Perth, Western Australia
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