Wrong. The expansion of the coolant is solely due to the change in
temperature, as with a metal or any other material. There is no change of
state involved, as the coolant is still below its boiling point at the
pressure in the cooling system.
Robert Hancock Saskatoon, SK, Canada
To email, remove "nospam" from firstname.lastname@example.org
Somebody flunked basic physics.
To apply that to this situation: The state of the coolant as it stays in
a pressurized cooling system is going to be different from when you
*depressurize* the same. If you equalize the pressure, of course you're
going to get steam! But in and of itself, that doesn't mean that the
coolant had boiled prior to you messing around with the radiator cap.
So is mine. From '74 Chevy Suburban with the 454 engine, to the '86 and
'87 Buicks, the '87 Cavalier, to the 1993 Cadillac, to the 1999 Chevy
Blazer, and my 2002 Pontiac Grand Am. And some were maintained by their
owners, and others taken to shops for service (for those relatives who
couldn't be bothered to maintain the car themselves or have one of the
more knowledgeable in our family do it). And I can tell you that of the
cars that used DEX-Cool, NONE of them have had a problem with it. Of
course, we've also been wise enough not to assume that just because DEX
was good for the engines with it, that it was also good for the engines
that came with the green stuff.
Now, I mean no offense with what I'm about to write, honestly. But has
it crossed your mind that other than the DEX Cool (which has people on
both camps who swear by it and against it), there's one other linking
factor among all the GM cars your family has owned? Particularly, that
one person was responsible for maintaining the cooling system on all of
these cars, and presumably followed the same procedures and got the SAME
results each and every time? Especially when other folks are
religiously following certain other procedures (keeping the tank full,
checking the system from time to time, etc) and have not had a problem?
And for the record, yes, I think GM made a mistake with Dex Cool. That
being that they wanted a maintenance free, long life coolant that was
very forgiving of boneheaded mistakes like letting the coolant level run
low or letting a Jiffy Lube kid dump green fluid into a tank filled with
orange fluid. Unfortunately, it requires just as much attention as
silicate-based coolants, and if people don't give it that attention,
then you run into trouble.
In all fairness, I just tried the example experiment with a used, needless
syringe (my Dad is a diabetic). I could not get it to "boil" pulling the
plunger fast or slow. The only bubbles I saw occurred when I left my finger
on the syringe to where air was able to get in. That isn't boiling.
Boiling is when water changes from a liquid to a gas. What the syringe did
was simply let in air. He is right that water expands when cool / frozen.
A lot of that also depends on the ratio of water and coolant. After all, it
is boiling that causes a boil over right?
2 cars then that originally had DEX-COOL gave you no problems? Glad to hear
it didn't. Keep in mind most people, including myself, wanted to switch
their older cars to DEX-COOL to get the long life benefits it offered.
Thousands of people tried this. Some have had no problems, but most have.
The funny thing is that some with DEX-COOL from the factory have problems.
I don't think anyone has an exact answer as to why DEX-COOL slugs, makes
mud, makes red cement, etc. since it is advertised as being compatible with
green. I think it is air and hot temperture.
That is understandable on your part. Understand that I checked the coolant
level in the overflow tanks weekly at first then about twice a month after
noticing the coolant remained at the same level in the overflow tanks.. I
just had different problems. The smoke coming out of the S-10, the gasket
in the Lumina going bad, my mom's Monte with the red mud, etc. Since giving
up on DEX-COOL, I have seen no problems with what I still own personally and
work on for my family.
The other thing too is that it may make water pump seals last longer, but it
doesn't protect the metal nearly as well as conventional green. Through
doing research on G-05, I have read on several webpages that the reason Ford
and Chrysler didn't go OAT when GM did is because of water pump, seal, and
gasket damage they discovered in their testing. I guess GM put too much on
the line to back down from it. Probably explains the lawsuit to some
degree. They have now gone to G-05 which is an HOAT coolant containing low
silicates to protect not only the metal of the water pump better than OAT /
DEX-COOL does, but also protect other metals better including metal. Zerex
5 year / 100,000 mile conventional green in the white jugs is also a low
silicate formula and is what I am running and having great luck with.
In all fairness to GM, my grampas 97 Silverado (I think that's at ~125k
miles and he just changed the Dex-Cool) and my uncles 99 Safari have
Dex-Cool and haven't had a problem. Yet our 99 Blazer had the sludge build
up (which GM paid to fix and convert to green antifreeze) and we had no heat
in the middle of a Wisconsin winter. I can guarantee that the overflow tank
was at the full line every time we checked it (hot line when hot and hot
line when it was cold). That brings up a question though, how can 2 same
engines (the Vortech 4300 in the Safari and Blazer) have 2 very different
results with Dex-Cool ?
I can't really answer that question to anybody's satisfaction.
I've seen all of the above vehicles with sludging problems in
our shop, but the Blazer's are by far the worst. I'm sure that
you kept your coolant level up, but most customers don't.
And often the coolant level in the rad can be low, while the
overflow is full. This is because the rad cap gets so bunged
up that it can no longer pull the coolant back into the rad
as the coolant cools down.
Man to much to reply to and catch up on....
My mom has a blazer and it was sludged up. I think there may be a
component or type of metal inside the system that causes dexcool to sludge
up. Does anyone know if the heater core is aluminum or not? Lets say you
have a copper heater core and a aluminum radiator. Thats going to be a
problem because the those two different types of metal will act as a mild
battery and will cause corrosion in the cooling passages. I highly doubt
GM would have made that mistake but some "bean counter" might have changed
some fitting or something to lessen the cost somewhere along the way...
Anyhow we had it flushed and new dexcool put in a few years back. It looks
pretty clean to this day.
Lets keep some things in mind here. The 15 psi rad cap is designed to
raise the boiling point of coolant so when you see 200deg it is not
steaming or even boiling in your engine. When you start overheating lets
say 250 deg then the coolant is boiling. When you open your cap or your
hose blows it hits the atmosphear and becomes steam. Its unlikely it was
steam before that.
If there is air in your system yeah it will expand like crazy and flood
out your overflow bottle. If there is no air in your system should see
very minor changes in the level of your overflow bottle like I do.
As you responded BTJ about the filling to the hot mark. No its not crazy
its only a half inch differance and then you still have about 3 inches
above that to go. Likely hood of that bottle overflowing with no air in
the system is zero if it doesnt go past 220.
Poor dexcool in a glass and let it sit. Let me know when it becomes
I've just started a job of pulling off the intake of my dads 98 truck. It
was supposed to have dexcool in the system but someone before him had
redid the system with conventional coolant which was a horrible mistake. I
pulled off the water neck and there is 1/8th inch of crystalized material
from the silica in the coolant caked up on the passages in various spots.
THIS IS WHY trying to switch to dexcool after the green crap is
"impossible". It WILL NOT come out of the system so it will contaminate
dexcool no matter how many times you try flushing the system. I took
pictures of this crystalized silica coolant crap and I'll put it up
sometime soon if you want to see it. I raked at it and it was pretty damn
well bonded to the aluminum. A chemical cleaner wont pull that stuff off
and out. It would take a media blaster to clean it off.
You are putting out information as if it were fact. As if people never had
problems with conventional coolants. You have got to understand that 5
year 150k miles doesnt mean it will last that long. It means it can last
"UP TO" 5 years 150miles given its not contaminated or low. You still have
to watch and maintain the system like any other system. If dexcool is
looking sludgy in a 3-4 year old car does that mean they should switch?
NO! Just drain it out and refill it. The likely hood of dexcool clogging
the system is FAR LESS than silica based coolants that actually BONDs to
metal and block passages. Dexcool sludge brakes up and off into
circulation far better than silica crystals and dexcool sludge does not
eat away at aluminum like a sand blaster. That is the important factor for
dexcool being used, not the long life of it.
We had ours flushed and refilled with Dex-Cool last year in October I think
and it got all sludgy again within a week.
My dad has a car with the green antifreeze and we had Dex-Cool laying around
and he thought that since his looked kind of low he should put in more
coolant. My uncle and I told him some of the stories about where people
mixed Dex-Cool and regular coolant and he immediatly flushed it and put in
the green stuff. Luckily nothing noticeable has happened yet.
We didn't switch, the GM representative told the dealership to forget about
Dex-Cool after trying to replace it once and to put regular anti-freeze into
the Blazer. We've had 7 or 8 trucks with regular green antifreeze without
any noticeable clogging, and 1 Blazer that had Dex-Cool that clogged up, I'm
going to stick with personal experiance on the issue between Dex-Cool and
regular green anti-freeze.
Yeah I put DEX-COOL in my 1995 Pontiac Grand Prix GTP thinking it was
originally DEX-COOL until I found out otherwise. I only had it in there for
3 days. Glad I got it all out but I did it by back flushing the cooling
system several times and running a chemical cleaner for 4 - 6 hours.
Me too. After seeing all that damn red mud in my Mom's car, I am sticking
with green. I am curious to talk to people that have switched either from
green or DEX-COOL to G-05 and see if they have had any problems. I honestly
believe that GM will eventually go to G-05 or something else. We'll see how
this class action law suit goes.
DEX-COOL is suppose to work with all metals...
http://www.prestone.com/products/14.htm (NOTHING ABOUT METAL)
Jesus Christ people! How many times do I have to say it? It is "near the
beginning of the steam process". I have never said that the damn coolant
and water are steam. DUH! It becomes steam due to the differences of
inside and outside temperature.
Of course it won't become muddy. You are forgetting the heat from the
engine and the air inside the engine.
Of course it was caked up since the system was not BACK FLUSHED! You have
to back flush several times to get it all the DEX-COOL out in conjunction
with running a good chemical cleaner that you are suppose to leave in for
4 - 6 hours.
What information have I put out as if it were fact? I know that DEX-COOL
will not last 5 / 150,000 but most of the public doesn't know that and
assumes that to be true by looking at the owner's manuals of their new GM
cars and seeing the DEX-COOL bottles in the stores. The bottom line is that
antifreeze / coolant is not suppose to slug! If it does that means it is an
inferior product. I think For and Chrysler discovered this and that is the
exact reason they stayed with conventional green and have just gone to G-05.
I also recommended using Zerex 5/100 Conventional Green coolant as it is a
very low silicate formula...
Also keep in mind that the whole point of DEX-COOL was to extend the life of
coolant and to cut down on water pump wear. GM was tired of giving away
free water pumps but I think their main supplier of coolant was Prestone &
Texeco at the time and their conventional green coolants are high in
silicates. No matter what coolant you run, replace it every 2 - 3 years.
You're using Chrysler as a gage for this? Thats funny considering I have
seen so much bs in their cars.
The zerex "EXTREME LIFE" not "extended life" is said to be compatable with
I suggest everyone read through these and come to your own conclusions.
What ever you decide to switch to, if you feel you need to drop dexcool
out of your system, make sure to use a silica and phosphate free coolant
so it stands a chance of being switched back and so aluminum parts dont
get ate up.
It means it is inferior dipshit. I have never heard or seen conventinal
green slug. I sure as hell have seen DEX-COOL slug. Coolant is not suppose
to slug no matter what. Contamination? You mean that green has been
introduced? BULLSHIT! The slug problem is the basis the the class action
lawsuit against GM on DEX-COOL.
No I am not using Chrysler as a gage. G-05 has been in use for at least 20
years by Mercedes and John Deere. Chrysler and Ford recently converted to
it after extensice tests the apparently GM didn't do. Ford was going to go
to an OAT coolant back backed down. Why? They found out about slug and
gasket and seal leaks.
Where did that pop out of? That has nothing ot do with the paragraph in my
post that reply was for.
Your first link is one of the beliefs of what is letting air into the
cooling system. GM is recommending S-10 owners go to Stant caps. That
might get rid of the air and therefore the slug, but the point is that
coolant is not suppose to slug no matter what to begin with. Contamination
is not the issue here. These people have not poured in or mixed another
coolant with DEX-COOL. It is simply slugging because it is an inferior
Your second link has more ads than story, but the story explains why
DEX-COOL sucks. The author though has his doubts. I propose this question
to that author. If you are not convinced that DEX-COOL is the cause, then
how can you explain why this doesn't happen with green conventional coolant
in the same systems upon their being completely flushed of DEX-COOL though
back flushing and running a chemical cleaner?
Yes. Heavily silicated coolants are bad. Use either Zerex G-05 or Zerex
5/100 Conventional Green coolant which have low silicates. Too many are
bad, but the right amount will protect those aluminum parts wonderfully for
about 2 -3 years. After that, change your coolant.
Because DEX-COOL sucks and the level was low in your radiator. If you
filled your overflow tank to the hot line when the engine was cold and it
was at the same level when the engine was hot then the radiator had to be
low. DEX-COOL doesn't like playing with air. How is it running with
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