OK, some of you may recall a thread where a user had some questions about coolant types and the amount of water in the mix. This triggered a discussion that I cant find to post this in, and it also made me to a little experiment. These are accurate results under controlled conditions in my home.

Temperature through the whole test is between 22-25 degrees, thats the temp my house has been set at all winter. All the bottles were rinsed clean and only ever had water in them before. The water is from a 2L bottle of Evian water, the tap water is Edmonton city tap water from my tap, the coolants are off the shelf bottles that were opened for the test to rule out contamination. None of the bottles have been touched since placed on the shelf.

Initially I wanted to test to see if the water separates from the coolant over time. The question came onto my mind when thinking of years back when I worked in a shop. We had the large drums 200 litres or so, that were mounted on angle on a shelf with premix in them and a spigot to open to let some out the bottom - a gravity fed system - so it would not aggitate the mix inside to stir it up. I was curious if those drums would eventually separate some when not used for a while. So if you didnt sell any dexcool for a month, and then poured 8L out of the tap on the bottom - would it be pouring out 50/50 like you think, or would it maybe pour out 70/30 cause its been sitting?

So here is the experiment that I set up:



The 2 bottles are only half full as I didnt go buy a bottle of water yet
The date of this photo is (will edit in later but its approximatly 3 months ago)

Now here we are on April 16. None of the bottles have been touched, but they have been examined up close by nearly every guest to my basement (they have to walk past them on the way up and down) and everyone sees the same results and is disgusted.



You can see that EVERY bottle that has ANY amount of dexcool in them has a scum ring just like in a bathtub, in fact, the one with the least amount of scum ring is the one with the mix of the two coolants. As well as a scum ring, there is also some scum in general on the clear surface of the bottles. It would appear that the green stuff is the only thing that can keep the scum from happenning. Another observation is that there is some mystery black solids floating on the top, and settled on the bottom. It happens in both the bottle and tap water at the same amount. The scum ring is a brown color and also is just as bad in both tap and bottle water.

I also carefully dipped my hydrometer in the 50/50 bottles, and the mix at the top, and the mix at the bottom ARE STILL 50/50 as they were in the beginning of the test. So it seems that even 3 months later the mix stays true. My initial question is answered.

So my results:

-It does not matter whether you use tap or bottled water, dexcool is still going to scum up - green is not going to scum.
-Mixing the two coolants does not seem to make any difference, in fact this will make your regular coolant live longer probably, but it will also reduce the amount of scumming that is going to happen in a cooling system using dexcool. It would seem that a 25/25/50 reg/dex/water mix would be beneficial to you however further testing should be done to see if this is a good idea.
-Dexcool when added to water creates some kind of black solids, as well as a brown scum in the air pockets in the cooling system, that will most definatley lead you to problems down the road.

So if anyone is a lab technitian and wants to test the scum, I would send you some in the mail!!!

This was very interesting and eyeopening to me, and I will never be using Dexcool for anything but poisoning critters again (its a joke). I wont let my friends use it now, and after seeing these bottles none of them want the orange stuff in their cars. Interesting indeed.

Here is some more photos, they are in order 12-34-56 in relation to the group photos. I will also try and get some of the even closer ones that my brother took with his real good camera from him.













Discuss.

 

Nice experiment! I wonder what would happen if you introduce heat into the experiment?

 

Neither tap water nor bottled water are pure H2O. They all contain outside contaminants (minerals, etc) which is likely what you are seeing. That is why it is recommended to use distilled water.

Also, what brand did you use for both coolants. I'm betting the green is the same Ethylene Glycol coolant as dexcool just with a different additive package. Propylene Glycol (old green) isn't used in coolants anymore because of the environmental concerns.

What was used to clean the bottles? How old were the bottles?

The devil is in the details.

To really do the comparison properly, distilled water should be used. Jugs of distilled water should be the starting point, the brands and/or the specific type of coolant should be listed, and... Just lost my train of thought and have to get on to other things.

It's a nice experiment even with the items I have pointed out. The fact still remains that the vast majority of all Dexcool applications are still running without any concerns well beyond one hundred thousand miles. For me, Dexcool performs very well, I have never have had a problem with it, and will continue to use it. Choose whatever makes you sleep better at night.

 

The experiment definitely shows what happens when you use regular tap or bottled water with Dexcool. I can't even get distilled water where I live, unless I distill it myself.

 

No supermarkets or even a Wal-Mart?

 

Nearest Wal-Mart is an hour away. We have 2 grocery stores. They sell gallons of bottled water, but I don't think it's distilled. I live in the woods, man. We still have a few people with real stills lol.

 

One of the few receipts I received with my '97 Blazer was one showing it had a major tune up done along with the intake manifold gasket issue taken care of (replaced) around 105k miles. Another showed it had the radiator replaced recently. It had no antifreeze in it at all when I bought it, the heater core gurgling (to this day) here & there. The new radiator had the brown sludge (really, a film) somewhat inside the filler neck. Oh well, probably had something to do with that DexCool scandal. Anyway, no issues. Added a gallon of AutoZones standard green (and cheapest) before winter. Amazing the different colors of antifreeze there is now. With the 4.3 being cast iron, it can take the abuse even better than aluminum, for which all these multi colors are designed to protect. Any color will work, even better if it is the same color.

 

Too me this proves nothing. Except if you mix these together they all have color & stay mixed in a bottle at room temp.
What happens when you add heat as stated above? then add heat & metal & oxidation with it then heat it & cool it hundreds of times? What about the chemical changes caused by all the variables when you introduce all the facts that happen in a REAL WORLD VEHICLE?

 

Great idea for an experiment.
- if you were just looking at testing to see what is up from the pre mixed in a drum to see if there is seperation this test would suffice
- Interested to see what the scum ring is and what part of the coolant would be settling out from this, this shows the purpose of this test which is to test seperation sitting over a period of time, but this test is invalid for use in a vehicle as several variables are not addressed.
- I agree that the bottled water should be distilled water for a proper test.
- I would like to know what that scum is, possibly a sealant or lubricating agent? just because it is settling out does not mean its bad, what would be nice to see is after it sits for a long time and you shake it up what happens to the scum ring, does it leave a residue or dissolve, and does if not does it dissolve under heat.

- For a proper test of coolant quality other variables have to be addressed such as addition to temperature changes (a large range ex. -40 ->100), documentation of the rate of scum formation over time as in general a vehicle would not sit longer than a week between use, which will mix the coolant up, the addition of materials that would be in contact would also be required,i.e. metal, hose, etc. to see how it reacts and what the influence if any.

So for the purpose stated for this experiment of storage of coolant the test holds valid. For the purpose of coolant quality further test is needed (is the scum good or bad). And for the purpose of effectivness etc. of coolant during use further testing is needed.

Great idea and interesting to see!

 

I didnt even think to use distilled water cause every garage that I have worked for has used the hose to mix the drums of coolant up - or used premixed gallons.

The purpose of the experiment was to see if the jug YOU have had sitting in your garage separates into water and coolant over time. That would mean the jug that you need to top up your truck might have separated, so maybe you just poured a litre of green water into your truck not 50/50 like you may think?

One of these days I will bring myself to shake the bottles up and see if I can get that scum to mix back into the stuff. I think Ill wait until the 6 month mark to check separation again, then do it.

All I know, is that even if my pals at work will give me dexcool jugs for free, I will instead be going and buying the green stuff from this day on.