is using not diluted coolant harmful

[alf]

Hi,

my mechanic used a gallon of Zerex G-05 and toped it off with distiled
water (I guess it is about 85/15 mix now) when changing the coolant.

Is using almost not diluted coolant harmful in anyway or should I rush
to change it again with proper 50/50 proportions.

thx for an insight

Andy

 

[DK]

Hi,

my mechanic used a gallon of Zerex G-05 and toped it off with distiled
water (I guess it is about 85/15 mix now) when changing the coolant.

Get manual and find out radiator capacity. Any chance it's 2 gallons?

Is using almost not diluted coolant harmful in anyway or should I rush
to change it again with proper 50/50 proportions.

I think 85/15 should not be dangerously harmful in the short term but
it will not cool as well because ethylene glycol has lower heat capacity
than water. On the other hand, 85/15 mix won't freeze well into -50C

DK

 

[alf]

Get manual and find out radiator capacity. Any chance it's 2 gallons?

just checked the manual - it is 7.1 qt, so my worries are gone.

I somehow misread it before and thought it is 5.1qt.

thx, A.

 

[y_p_w]

Get manual and find out radiator capacity. Any chance it's 2 gallons?




I think 85/15 should not be dangerously harmful in the short term but
it will not cool as well because ethylene glycol has lower heat capacity
than water. On the other hand, 85/15 mix won't freeze well into -50C

Isn't the lowest freezing temperature for an ethylene glycol
and water mixture -84F -64C at about 70% concentration?

One problem in general is that ethylene glycol is more
viscous than water. Not only does it have lower specific
heat but it's not going to flow through the cooling system
as quickly.

 

[DK]

Isn't the lowest freezing temperature for an ethylene glycol
and water mixture -84F -64C at about 70% concentration?

My number was pure guesstimate - I just knew it's gotta be
below -50C I don't think ethylene glycol at 85% will freeze at
higher temp than 70% would, but that difference is pretty irrelevant
here. (Although, to think of it, if the miscibility of EG and H2O
decreases significantly with temp, I can imagine that at
sufficiently low temp you could get water islands nucleating and
triggering freeze at lower temperature; maybe).

One problem in general is that ethylene glycol is more
viscous than water. Not only does it have lower specific
heat but it's not going to flow through the cooling system
as quickly.

Certainly, that too. It's also denser.

DK

 

[y_p_w]

My number was pure guesstimate - I just knew it's gotta be
below -50C I don't think ethylene glycol at 85% will freeze at
higher temp than 70% would, but that difference is pretty irrelevant
here. (Although, to think of it, if the miscibility of EG and H2O
decreases significantly with temp, I can imagine that at
sufficiently low temp you could get water islands nucleating and
triggering freeze at lower temperature; maybe).

I'm having a hard time finding an actual chart of ethylene
glycol/water mixtures and freezing temps other than bottles
of antifreeze that stop at 70%. The freezing temp of pure
ethylene glycol is supposedly higher than even a 50/50
mixture with water.

It's one of those strange things where mixing it with water
creates an effect that lowers the freezing temp to below
that of either alone. The following states that maximum
freeze protection is at 67% ethylene glycol (-84 deg F)
and pure ethylene glycol freezes at 8 deg F.

http://www.peakantifreeze.com/tech/tech_c.html

I'm not sure what it would be at 85%, but I don't think
it's terribly beneficial. I would try to get the
concentration down to about 50% if it were my car. I
don't really encounter anything lower than subzero temps
even when I head for the mountains. I'm generally more
worried about cooling.

 

[houndman]

Hi,

my mechanic used a gallon of Zerex G-05 and toped it off with distiled
water (I guess it is about 85/15 mix now) when changing the coolant.

Is using almost not diluted coolant harmful in anyway or should I rush
to change it again with proper 50/50 proportions.

thx for an insight

Andy

since you guys are talking about AF, I heard that the ph of it should
be checked twice a year, so acids don't eat up plastic parts. I also
heard that 10% will keep the coolant from freezing solid, and just
turn to slush. I have no idea what % I have. I was changing mine, and
found mineral deposits in the upper tubes of my Chevy, and had a small
leak in the radiator. I rodded out the tubes, and put in stop leak
till I could solder the leak, and haven't gotten back to it. I am
disabled, and it has been a Few yrs. I probably tested it, but can't
remember. It is green, and hasn't had a problem. Though one time the
leak opened. It probably slushed up, and disturbed the stop leak.)

VF

 

[Rick Courtright]

Hi,

Years ago, it seems most antifreeze jugs had a little chart on the
back...

From memory, about a 70% concentration produced the lowest freezing
temp, as well as the highest boiling temp. Above 70%, both numbers
actually started getting worse.

The boiling temp difference between a 50% and a 70% concentration is not
really that significant (maybe 10-11 def F?), and even if one were to
overheat enough to boil a 50% mix, most of today's engines would already
be damaged. For those who live in truly hot climes, it's interesting to
note that pure water actually cools BETTER than a heavy coolant mix, so
a 10% solution is sometimes recommended simply for corrosion protection.

I've also heard, though I can't verify it, that while ethylene glycol in
combo w/ water protects against corrosion, in 100% concentration, it's
actually corrosive (one of the reasons it's not recommended in engines.)
Anyone have any info in that department?

Rick

 

[DK]

Hi,

Years ago, it seems most antifreeze jugs had a little chart on the
back...

Just looked at the chart on my coolant jug. It only goes to
70% of the concentrate with corresponding freezing point
-84F/64C

From memory, about a 70% concentration produced the lowest freezing
temp, as well as the highest boiling temp. Above 70%, both numbers
actually started getting worse.

Hmm, could be, for ethylene glycol. Although it's definitely not true for
alcohols - freezing point of 100% ethanol is lower than any of its
aqueous solutions.

I've also heard, though I can't verify it, that while ethylene glycol in
combo w/ water protects against corrosion, in 100% concentration, it's
actually corrosive (one of the reasons it's not recommended in engines.)
Anyone have any info in that department?

No, ethylene glycol by itself is not corrosive at all. But pure ethylene glycol
is hygroscopic and usually ends up with some water. High EG
concentration + some water + heat = acid production. Acids are
corrosive. And acidic pH promotes formation of more acid. That's why
commercial coolants contain pH buffers. I'd imagine if your coolant,
diluted 10X with pure water, give pH >7.5, there is nothing to worry.
If it gives pH < 7.0, it's probably a good idea to change it ASAP.

DK

 

[y_p_w]

Just looked at the chart on my coolant jug. It only goes to
70% of the concentrate with corresponding freezing point
-84F/64C

I think that's approximate. The link I had from Peak Antifreeze
stated 67% was the ideal concentration for lowest temperature
freeze protection, at -84 deg F.

Hmm, could be, for ethylene glycol. Although it's definitely not true for
alcohols - freezing point of 100% ethanol is lower than any of its
aqueous solutions.

I knew someone who bought some vodka and chilled it in the
freezer. I've tried it myself and darn it if it didn't freeze
over. Made for a very cool shot.

No, ethylene glycol by itself is not corrosive at all. But pure ethylene glycol
is hygroscopic and usually ends up with some water. High EG
concentration + some water + heat = acid production. Acids are
corrosive. And acidic pH promotes formation of more acid. That's why
commercial coolants contain pH buffers. I'd imagine if your coolant,
diluted 10X with pure water, give pH >7.5, there is nothing to worry.
If it gives pH < 7.0, it's probably a good idea to change it ASAP.

I believe at least one of the two major organic acid corrosion
inhibitors serves as an alkaline buffer.

Supposedly straight propylene glycol won't freeze over, but
will just turn to slush. I've heard of a few 100% propylene
glycol cooling systems.