During a coolant change I somehow I miscalculated something and only have protection down to -7F. Want it at least to -30F. Is there an online calculator that tells you how much coolant in the system to replace with 100% antifreeze? I know the capacity is 10 quarts excluding the overflow bottle. Current freeze point -7F. Desired freeze point -30F. Yea I know I could just guess and replace maybe 2 quarts, but a calculator would be more accurate and less wasteful.
How much coolant to replace to increase to 50%? Any online calculator?
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I found this calculator recently, but have not tried it: http://www.csgnetwork.com/coolantpercentcalc.html
Also, over the many years of servicing ag. equipment at work, I have learned that sometimes (often) the stated capacities in owners manuals are way off. John Deere is especially bad. My industrial Kohler generator was also way off.
It was so bad that I invested in a refractometer to measure coolant strength. Once you use one, you will wonder how you survived without it.
Also, over the many years of servicing ag. equipment at work, I have learned that sometimes (often) the stated capacities in owners manuals are way off. John Deere is especially bad. My industrial Kohler generator was also way off.
It was so bad that I invested in a refractometer to measure coolant strength. Once you use one, you will wonder how you survived without it.
Originally Posted by doitmyself
I found this calculator recently, but have not tried it: http://www.csgnetwork.com/coolantpercentcalc.html
That doesn't calculate how much to replace. I did find this: https://www.1728.org/radiator.htm which is what I need but has percent instead of degrees, but my refractometer has both readings, so ok.
I found this calculator recently, but have not tried it: http://www.csgnetwork.com/coolantpercentcalc.html
That doesn't calculate how much to replace. I did find this: https://www.1728.org/radiator.htm which is what I need but has percent instead of degrees, but my refractometer has both readings, so ok.
Does the side of the jug got any charts? I always drained the block. Then I started pouring in straight coolant until I had added 1/2 the capacity. of the system. Then top off with water. Do you have a tester? 5 balls is optimum.50/50 is good till -40
Like I said, I have a coolant refractometer. Shows percent concentration and degrees. Ball tester so old fashion.
Give me the percentage, and the arithmetic is simple.
But temperature is useless in this calculation.
But temperature is useless in this calculation.
![[Linked Image]](https://images.matthewsvolvosite.com/antifreeze-coolant-mix-chart.png "[Linked Image]")
So -7 F says you have 7/19 concentration, or 36% EG. 3.6 quarts of antifreeze and 6.4 quarts of water in your 10 quart system.
If you dump half of it, you'll have 1.8 quarts of AF and 3.2 quarts of water remaining. It's unlikely you'll get more than half if you dump the radiator and hoses. Block drains are something of a hassle. You'll want to measure what actually comes out.
Assuming you get your 5 quart drain, refill with 3.2 quarts of 100% AF then top off with no more than 1.8 quarts of water. (You should measure out this water and ensure you get it all in there or else you have trapped air.) If you get more than 5 quarts, do as above then mix 50/50 and top off with that.
Notably, this is as accurate as the hysteresis between whether x balls float or y do, which is the biggest variable in this.
Like Astro said, the math is pretty simple if you know your target %, current %, and system volume.
Using this graph I found on this site: https://forum.miata.net/vb/showthread.php?t=632985
![[Linked Image]](https://www.bobistheoilguy.com/forums/attachments/usergals/2019/07/full-60362-34123-ant_freeze_protection.jpg "[Linked Image]")
Lets say your currently at -6F freeze point (since that's conveniently 40% on the graph) and your cooling system holds 2 liters. That means you're current system is has 0.8l coolant, 1.2l water. If your goal is 50% concentration, you need to take out enough water (and unfortunately coolant) so that your system has 1l of water left. That means you need to remove 0.2l of water. At the present 40% concentration, if you remove 0.333l of the mixture (0.2l/.6l), you're, you're removing 0.2l of water and 0.133l of coolant. But, more importantly, at that moment, your system has 0.667l of coolant and 1l of water. Then, you top off your system with undiluted coolant (0.333l, or to system capacity of 2l) and there you go, you have a 50% mixture.
So, the equations are:
X = system capacity
Y = current percent antifreeze
Z = target percent antifreeze
X*(1-Y) (total amount of water)
X*(1-Z) (target total water)
X*(Y-Z) (total water to remove)
Remove this quantity:
X*((Y-Z)/(1-Y)) (total current coolant to remove)
Then top off with undiluted antifreeze until full.
Using this graph I found on this site: https://forum.miata.net/vb/showthread.php?t=632985
Lets say your currently at -6F freeze point (since that's conveniently 40% on the graph) and your cooling system holds 2 liters. That means you're current system is has 0.8l coolant, 1.2l water. If your goal is 50% concentration, you need to take out enough water (and unfortunately coolant) so that your system has 1l of water left. That means you need to remove 0.2l of water. At the present 40% concentration, if you remove 0.333l of the mixture (0.2l/.6l), you're, you're removing 0.2l of water and 0.133l of coolant. But, more importantly, at that moment, your system has 0.667l of coolant and 1l of water. Then, you top off your system with undiluted coolant (0.333l, or to system capacity of 2l) and there you go, you have a 50% mixture.
So, the equations are:
X = system capacity
Y = current percent antifreeze
Z = target percent antifreeze
X*(1-Y) (total amount of water)
X*(1-Z) (target total water)
X*(Y-Z) (total water to remove)
Remove this quantity:
X*((Y-Z)/(1-Y)) (total current coolant to remove)
Then top off with undiluted antifreeze until full.
Originally Posted by eljefino
Assuming you get your 5 quart drain, refill with 3.2 quarts of 100% AF then top off with no more than 1.8 quarts of water.
Don't understand. Why top off with water? I need to drain the existing mix x quarts and refill with the same x quarts of 100% AF. Anyway, the -7F is 37% so using the calculator at: https://www.1728.org/radiator.htm Radiator Volume = 10, Present Antifreeze Percentage = 37, New Antifreeze Percentage = 50. Volume To Be Drained = 2.0635.
Assuming you get your 5 quart drain, refill with 3.2 quarts of 100% AF then top off with no more than 1.8 quarts of water.
Don't understand. Why top off with water? I need to drain the existing mix x quarts and refill with the same x quarts of 100% AF. Anyway, the -7F is 37% so using the calculator at: https://www.1728.org/radiator.htm Radiator Volume = 10, Present Antifreeze Percentage = 37, New Antifreeze Percentage = 50. Volume To Be Drained = 2.0635.
Take a good sized sample from your radiator and gradually add (while keeping track of how much you're adding) more A/F until it reaches the desired level of protection. Calculate the percentage you needed to correct the sample. Now adjust your system to that same percentage.
Drained 2 quarts, filled with 2 quarts 100% AF. Got to take it for a drive to get it mixed, then let it cool to test.
This is exactly why I always mix antifreeze in a bucket before I put it in the engine.
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