Ted,

Thanks much for your thoughts. By the way, I do realize I could completely
bypass the heater core and eliminate the leak, but would like to retain the
rear heater if possible since winters here in Chicago can be cold. From
brief visual inspection, the leak seems to be coming from outside the
passenger compartment, but as you suggest it will likely need to be opened
up to confirm that. If I go to that trouble, then I may just elect to
replace the heater core completely since it is now going on 10 years old.
If anyone has replaced the rear heater core and can provide advice/comments
on difficulty of that job, it also would be appreciated.

On the G-05, I've been operating thus far on a 4-year and roughly 40K mile
cycle on my other vehicles and have not had any problems yet, so that is why
I asked. For the record, I do the complete Prestone chemical flush (drain
coolant, fill with tap water, add chemical, bring to operating temperature,
then drain), then backflush afterward with a garden hose, then refill with
tap water and bring back up to operating temperature twice to rinse the
chemical, before refilling. The real issue here is time for the vehicle to
cool down between each of these fills/drains, so as you can see it takes
considerable time. Since I do this now with the 2-year stuff too, I was
looking to save half my labor by going to the 4-year cycle with G-05.

To clarify my original question, I want to know if anyone is aware of
anything in the chemical composition of the Zerex G-05 that is incompatible
with the 1999 3.8L engine design (water pump, block, heads, TStat, hoses,
radiator, heater cores, etc.) since the owner's manual specifies the use of
green, 2-year ethylene glycol. Again, thanks for taking time to reply with
your thoughts and suggestions.

Bob


"Ted Mittelstaedt" <tedm@toybox.placo.com> wrote in message
news:rhfrr5-onu2.ln1@news.ipinc.net...
>
> "Bob Shuman" <reshuman@removethis.alcatel-lucent.com> wrote in message
> news:48ea2797@news.alcatel.com...
>> Several months ago I replaced all of the rubber coolant/heater hoses on
> my
>> 1999 Town & Country Limited Minivan. Other than a few being a royal PITA,
> I
>> thought it went fairly uneventfully. A day later, I noticed a small drip
> on
>> my garage floor located just in front of the rear passenger side wheel.
>> I
>> suspect this is the rear heater core, and sure enough when I checked the
>> hose was lightly damp, so I tightened the hose clamp a bit more, but the
>> leak did not stop. The leak is fairly minor and I have been able to add
>> about 8 oz of 50/50 mix every month to maintain the proper level on the
>> coolant recovery tank.
>>
>> I now suspect that I could have possibly damaged the inlet tube fitting
>> going into the core since I recall that I was surprised to see that the
>> inlet tube actually pivoted in the horizontal plane when I replaced that
>> short rubber connector hose.
>>
>> Has anyone replaced this hose or the rear heater core before and if so,
> can
>> you confirm that the inlet tubes to the rear heater core are supposed to
> be
>> soldered in place/stationary? Given the situation, will I need to
>> replace
>> the core and if so, how difficult is this job, or can I apply a
>> simpler/cheaper fix (JB Weld, Epoxy, or have the inlet tube
>> re-soldered)?
>>
>
> You should be able to see from the fluid trail if it's coming from
> within the passenger compartment or just at the hose joint.
>
> My recommendation is to disconnect the 2 hoses going to the rear
> heater and couple them together, bypassing the core. If the leak goes
> away then you know it's the core.
>
> If the core is leaking your best bet is replacing it I think. You can get
> a radiator shop to resolder the inlet tubes but their labor would cost
> what
> a new core would. I wouldn't recommend JB Weld on a joint that is
> in the passenger compartment, in order to properly apply it anyway your
> going to have to take the interior panel off to get at the heater core and
> by the time you get that far you might as well replace the core.
>
>> Lastly, I've always used the standard green ethylene glycol (Prestone or
>> Peak 2-year change interval) mix in this vehicle. Can I use Zerex G-5
>> (5-year change interval) coolant in this vehicle like I do in my newer
>> Chryslers? Doing so would allow me to avoid doing the time consuming
> flush
>> and fill during the remaining expected ownership of this vehicle.
>>
>
> Personally I think the 5 year change mix is snake oil and in another 10
> years when we see a lot of used cars with rotted-out cooling systems
> people will figure that one out. If your asking for advice on
> jury-rigging
> you may as well know that a simple dump and replace of the mix in the
> radiator will get about 1/2 of what is in there, and if you do that every
> 2 years you will likely keep the anti-corrosion additive package
> adequately
> supplied. Lots and lots of people have gone for extended change intervals
> with the traditional green stuff mainly due to lackadasical maintainence
> and have suffered no ill effects.
>
> Flushing - if done properly (ie: backflushing) - gets rid of sediment
> that builds up. Just because you can make an anti-corrosion additive
> package last twice as long doesen't mean that sediment isn't still
> building up in the system at the same rate. There is always material
> loss from the materials (ie: hoses) as well as some oxidization - the
> cooling system isn't sealed - even though it may be happening at a
> lower rate - that all contributes material that settles out of the system
> into the nooks and crannies. I'm not convinced that the G-5 formulation
> reduces the rate that this happens at. Getting the chemical package to
> last longer is the easy part.
>
> Ted
>
>