I never really noticed a consensus here, so figured it would be worth
asking.
Our '94 Acclaim 3.0L came to us last year with DexCool in it (pink). The
factory shop manual says to use glycol, then adds all sorts of stipulations
to that, such as:
"50/50 Glycol and Water (.82 btu) is the recommended combination... The
radiator, water pump, engine water jacket, radiator pressure cap, thermostat,
temperature gauge, sending unit and heater are all designed for 50/50
glycol.
"Where required, a 56 percent glycol and 44 percent water mixture will
provide a freeze point of -59C (-50F).
"CAUTION: Richer mixtures cannot be measured with field equipment which
can lead to problems associated with 100 percent glycol." (this last is
all in boldface, and it makes absolutely no sense to me)
"The use of aluminum cylinder heads, intake manifolds, and water pumps
requires special corrosion protection. Mopar Antifreeze, Prestone II,
Peak or antifreeze containing Alugard 340-2, or their equivalent are
recommended for best engine cooling without corrosion. When mixed only to
a freeze point of -37C (-35F) to -59C (-50F). [sic] If it looses [sic]
color or becomes contaminated, drain, flush, and replace with fresh
properly mixed solution."
"Use only 50/50 concentration of ethylene glycol type antifreeze and
water."
The previous owner seemed to have most of his service done by a Plymouth
dealer. Could the dealer have substituted the DexCool for some reason?
Does DexCool make any kind of sense in this car? Why would they be so
concerned that the mix be between 50/50 and 56/44?
If it makes any difference, the current coolant registered about -45F
on my Prestone plastic tester (the kind with the large red plastic
needle indicator). I plan to replace the coolant soon anyway.

Signature
"...by March 2000, President Clinton informed Congress he could no longer
certify that 'North Korea is not seeking to develop or acquire the capability
to enrich uranium.'"
<http://www.pbs.org/newshour/bb/asia/northkorea/nuclear.html>
aarcuda69062 - 22 Oct 2006 21:48 GMT
<snip>
> "Use only 50/50 concentration of ethylene glycol type antifreeze and
> water."
>
> The previous owner seemed to have most of his service done by a Plymouth
> dealer. Could the dealer have substituted the DexCool for some reason?
How do you know it is DexCool? There are a number of different
coolant formulations that are pink/red/orange in color, among
them would be MoPar long life coolant.
> Does DexCool make any kind of sense in this car?
DexCool, no. Long life coolant, yes.
>Why would they be so
> concerned that the mix be between 50/50 and 56/44?
Assures adequate freeze protection, adequate corrosion
protection, adequate heat transfer, seal life.
> If it makes any difference, the current coolant registered about -45F
> on my Prestone plastic tester (the kind with the large red plastic
> needle indicator). I plan to replace the coolant soon anyway.
What makes a difference (to me) is using some cheap $3 tester to
check your coolant. Refractometers are pretty cheap now.
clifto - 23 Oct 2006 00:18 GMT
> <snip>
>> "Use only 50/50 concentration of ethylene glycol type antifreeze and
[quoted text clipped - 6 lines]
> coolant formulations that are pink/red/orange in color, among
> them would be MoPar long life coolant.
I'm glad you asked, even if I will look silly now. Among the things we
got with the car was a partially filled bottle the pink stuff by Prestone
(the silver bottle), which tells me the owner and not the dealer put it
in. I knew there was some reason the word stuck in my head (the bottle
says something about compatibility with DexCool).
>> Does DexCool make any kind of sense in this car?
>
> DexCool, no. Long life coolant, yes.
For my purposes it has to last one year.
>> Why would they be so
>> concerned that the mix be between 50/50 and 56/44?
>
> Assures adequate freeze protection, adequate corrosion
> protection, adequate heat transfer, seal life.
I don't see the problem with 60/40 or 65/35 or even 70/30 in that
regard.
>> If it makes any difference, the current coolant registered about -45F
>> on my Prestone plastic tester (the kind with the large red plastic
>> needle indicator). I plan to replace the coolant soon anyway.
>
> What makes a difference (to me) is using some cheap $3 tester to
> check your coolant. Refractometers are pretty cheap now.
Wow. I haven't even seen a refractometer since the sixties, when I worked
pumping gas at a station. Had a "turkey baster" specific gravity tester
but don't know what became of it. I'll have to look around for a nice
refractometer now.

Signature
"...by March 2000, President Clinton informed Congress he could no longer
certify that 'North Korea is not seeking to develop or acquire the capability
to enrich uranium.'"
<http://www.pbs.org/newshour/bb/asia/northkorea/nuclear.html>
DeserTBoB - 23 Oct 2006 02:58 GMT
>> Assures adequate freeze protection, adequate corrosion
>> protection, adequate heat transfer, seal life. <snip>
>I don't see the problem with 60/40 or 65/35 or even 70/30 in that
>regard.
Wrong. Heat transfer starts to fall off rapidly after 55 solution of
either ethynene or propylene glycol. Seals begin to leak due to low
surface tension and solvent action of excessive glycol. Ethylene is
acetic by nature; having too rich a mixture of it will promote
electrolysis and corrosion even with the additive package that comes
with it.
>>> If it makes any difference, the current coolant registered about -45F
>>> on my Prestone plastic tester (the kind with the large red plastic
[quoted text clipped - 7 lines]
>but don't know what became of it. I'll have to look around for a nice
>refractometer now. <snip>
A good investment. The hydrometers (the better ones) can be fairly
accurate IF the coolant hasn't been contaminated. The $3 plastic
things are useless, as are the "floating ball" things. It's getting
very hard to find good hydrometers for battery service now, as well. I
used to order my hydrometer parts directly from C&D (one of the big 3
battery makers in the US,) but they've since replaced their old Pyrex
hydrometers with cheap plastic ones.
hls - 23 Oct 2006 05:53 GMT
>>> Ethylene is
> acetic by nature; having too rich a mixture of it will promote
> electrolysis and corrosion even with the additive package that comes
> with it.
Sorry, Bob, but I have to challenge this one. Ethylene (and I assume you
meant to
write 'ethylene glycol') is not 'acidic' by nature. But its oxidation
products are, as are
most oxidation products. (That is why the old German chemists called oxygen
'säuerstoff'
or acid maker)
MaceFace - 22 Oct 2006 23:25 GMT
> Our '94 Acclaim 3.0L came to us last year with DexCool in it (pink). The
> factory shop manual says to use glycol, then adds all sorts of stipulations
[quoted text clipped - 6 lines]
> "Where required, a 56 percent glycol and 44 percent water mixture will
> provide a freeze point of -59C (-50F).
> "The use of aluminum cylinder heads, intake manifolds, and water pumps
> requires special corrosion protection. Mopar Antifreeze, Prestone II,
[quoted text clipped - 3 lines]
> color or becomes contaminated, drain, flush, and replace with fresh
> properly mixed solution."
> The previous owner seemed to have most of his service done by a Plymouth
> dealer. Could the dealer have substituted the DexCool for some reason?
> Does DexCool make any kind of sense in this car? Why would they be so
> concerned that the mix be between 50/50 and 56/44?
Why did you write "glycol vs. DexCool" when DexCool and almost every
automotive coolant are primarily ethylene glycol (a few, like Sierra,
are primarily propylene glycol)? The difference between DexCool and
other coolants is in the anti-corrosion additive package, and DexCool
lacks phosphates and silicates, the latter being part of the Alugard
package. I'd use major brand universal or G-05 coolant in a Chrysler.
The reason for limiting the concentration to 56% antifreeze is because
ethylene glycol conducts heat only about 50% as well as water does, so
too high a concentration can lead to overheating.
Steve - 23 Oct 2006 14:43 GMT
> I never really noticed a consensus here, so figured it would be worth
> asking.
>
> Our '94 Acclaim 3.0L came to us last year with DexCool in it (pink).
I seriously doubt that. It was probably Mopar-brand G-05 coolant, which
is also red (for some reason known only to the Mopar parts department,
other G-05 brands are a pale gold/yellow).
The
> factory shop manual says to use glycol, then adds all sorts of stipulations
> to that, such as:
OK, fact check time. ALL coolants (except Sierra and other
Propylene-glycol based "low tox" coolants) are ethylene glycol based.
Including DexCool. What differs between coolants is the anti-corrosion
additive package. These fall into 3 categories:
1) Traditional silicate (the old Prestone type, usually green in color,
but color no longer is definitive).
2) Hybrid organic acid technology coolants (aka HOAT). The most common
example is G-05, used by Chrysler, Ford, Benz, and a bunch of European
makes as OEM coolant. It has much lower silicate than traditional, but
still has SOME.
3) Organic Acid Technology (like DexCool) which has no silicates.
The most nearly "universal" type is #2- the HOAT coolants. The least
universal is #3. DexCool has caused huge problems in cooling systems not
designed to use it, and even in quite a few that GM had allegedly
designed for it. Your 94 Acclaim originally came with a silicate
coolant, and that will be fine to continue using (most parts-store
"house brands" are silicate coolants, made by Old World Industries
(parent company of Peak antifreeze). But it will also be fine using
G-05, available under the Mopar, Motorcraft Gold, and Zerex brands.
Whatever you do, do NOT use DexCool in it, though.