Coolant Mixture Check, Hot or Cold?

[MrAl]

I think you are over thinking this.

Drain coolant. Flush with hose for 20 minutes. Drain water. Close all hoses tight. Add 3.7 liters pure coolant ( 4 is fine)

Top off with water to full mark. Run car. Wait till it's cold. Add water to mark.

Repeat every 2 years

You can run 50-50 mix year round in NJ or even upstate NY

Hi there Steve,

You're absolutely right there, and i would do that, but this car was supposedly just done with new water and new coolant. So i was just trying to check it to make sure, that's all. I would do this same thing even if i filled it myself with new fluids.

But anyway, i have some results for the "tester" i bought the other day, and notice i put the word "tester" in quotes. That is because it's effectiveness with this car is questionable because it's hard to get a hot sample directly from the car. I'd have to take a sample from the car, bring it in, and heat it and test it. But the tester looks questionable and here are the results of the test of this tester.

In the results below the 'percent' is the percent concentration of pure antifreeze straight from the antifreeze bottle, and it's the concentrated kind not the pre diluted 50-50 type.

-----This was a test of the antifreeze tester------

All fluids room temperature, about 75 to 80 degrees F.
Starting concentration with distilled water: 0.000 percent
After 0 pure antifreeze additions: 00 percent, 3 balls floating
After 1 pure antifreeze additions: 20 percent, 4 balls floating
After 2 pure antifreeze additions: 33 percent, 4 balls floating
After 3 pure antifreeze additions: 43 percent, 4 balls floating
After 4 pure antifreeze additions: 50 percent, 4 balls floating
After 5 pure antifreeze additions: 56 percent, 5 balls floating

After heating this last solution the 5th ball no longer would float. As the test sample
cooled the fifth ball would start to very slowly rise again.

Notice one thing right away though, the first line there is with PURE DISTILLED WATER and i am already getting 3 balls floating! That indicates -10 degrees F, which is NOT what happens with distilled water.

So here we see that the tester tells me almost nothing when the fluid is cold, and i doubt it would do that much better when hot, although that fifth ball did sink due to the higher temperature.
All i know from the test on the car is that the solution in the car is somewhere between 20 percent and 50 percent, but not over 50 percent and maybe as low as 10 percent but from the color i doubt that. I might try the car sample and then heat it, or just try to get better resolution with this test.
Too bad they made this one for hot samples. I might just look around for a cold sample type.
Either that, or just drain the coolant tank, refill with pure antifreeze, then check again. That will probably give me 5 balls floating cold, which should be good i think. If not i'll have to repeat before
winter after the solution had time to mix with the rest of the engine water.

This also tells me not to trust the testers we buy from the Auto Stores

Thanks.

[abscate]

Do you have a postal scale? You could simply pour out a known volume of your coolant, weigh it, and then knowing the mass and volume you know the density - from which you can deduce the water- coolant mix.

AInt science a great thing??

Keep your pet rabbit away from that scale - that will upset the measurement - although you can tare your hare out.

[MadeInJapan]

Btw, you can test the fluid in your over-flow tank hot. The trick is to get the fluid to run into your engine past the thermostat. This means that the engine has to be running for 15-20 mins. If you let it idle and turn the A/C on in the cabin at full blast, this will help heat the engine up enough to open the thermostat earlier...then you will see the stream of liquid flowing through the overflow tank. Just keep the top off of it- don't wait until it's hot then open it or you'll have hot coolant spraying everywhere.

[MrAl]

Hi again,

Steve:
You think that a small sample of the mixture would weigh that much different than pure water? That and the tare weight of the sample container might skew the weight, but i've never tried this before.
Now that i think about it i dont know the weight of one gallon of antifreeze as compared to one gallon of water. I'll have to think about this and maybe look some stuff up.
LATER: found antifreeze weighs in at about 9 lbs per gallon while water is about 8 lbs per gallon. That's very roughly about 10 percent difference, which could be readable on a scale with good resolution, although in a 50 50 mix it would be about 5 percent. I'll have to check my scale to see how good it is. The amount measured would be compared to pure water and pure antifreeze, as well as a 50-50 mixture. I might get a usable reading
Thanks for the idea.

MadeInJapan:
I did run the car for at least 15 minutes and the thermostat did open up. The water in the tank never got hot though, and i even tried 'pumping' with the upper radiator hose by squeezing it repeatedly and letting go. Some of the hot fluid got into the tank but not enough to make it hot.

I think i am just going to get a 'cold' tester and be done with it. They sell them too for about 2 or 3 dollars. Of course i'll have to test that too first

[abscate]

My postal scale reads in grams

A small cup of fluid, about 500 ml, will weigh in at roughly 500g

You will get near 0.2% accuracy which will be fine

[MrAl]

Hi,

Yes thanks, i might try that soon. Was that 500mL pure antifreeze or a 50/50 mixture with pure distilled water?

I got a new tester the other day. It reads -20 degrees F for a 50/50 mixture. It reads -45 degrees F for a 56/44 percent mixture antifreeze/water. It's at least better than the other one because it says to test cold on the back of the package it comes in when you buy it.
Pure distilled water at room temperature reads close to +30 degrees F as near as i can tell (it is not made to go that high really), so although it may not be perfect it is MUCH better than the little one with the balls in it.
I'll try it on the actual car next.

My advice to anyone else using ANY of these testers though is to test the tester first with a small 50/50 mixture, at the very least.

[abscate]

Pure water ( tap or distilled ) will weigh 1g per mL, coolant will weigh more

The taller and thinner container you can make this measurement the more accurate it will be

Doesn't everyone have a volumetric flask in their house?

Make sure your monitors are ready before you measure this or QMT will throw off the reading

[MrAl]

Pure water ( tap or distilled ) will weigh 1g per mL, coolant will weigh more

The taller and thinner container you can make this measurement the more accurate it will be

Doesn't everyone have a volumetric flask in their house?

Make sure your monitors are ready before you measure this or QMT will throw off the reading

Hello again,

What is QMT?
How can the monitors interfere with the antifreeze concentration/

Thanks.

[abscate]

Your taking me too seriously Al. I was yanking your chain on the monitors not ready thread.

Sorry about that, Ill probably get another moderator warning for this, although apparently pHp doesn't let you...

You cannot warn yourself.

[cn90]

Or do an experiment on specific gravity vs temp with a mix of 50-50 in a metal pot.
Whatever you do, don't contaminate with food for obvious reason: antifreeze is toxic!

- Put in in freezer to get it down to -20C: measure with coolant tester and see where the arrow points to.
- Repeat with temp at 0C.
- Repeat with room temp 20C.
- Heat to 100C, measure again.

Once done, wait for it to cool down and save it for future use.

Anyone wants to do this experiment for the group? Remember high school chemistry class?

PS: I think the tester is designed for room temp.