Calculating coolant load after flushing.

[Colt45ws]

The CVPI had some...really nasty dark green coolant in it so Ive been flushing it with plain water. Seriously, the liquid coming out looks like it has stuff growing in it.
Ive only been draining the radiator. Based on how much water it takes to refill, Im changing around 1.9gal each time of a system with 4.75gal capacity.
Right now Ive done that twice, and I was going to do it one more time with water before refilling with coolant. Based on the work Ive done If I were to drain and refill with 100% coolant after that I would be short an insignificant amount, ending up about 45/55% coolant/water.

 

[Warstud]

Just test it when your done. A 50/50 mix should be good for temps as cold as -34F. IF not just drain some 50/50 from the rad and add some concentrate.

 

[SHOZ]

I always will drain the coolant and fill with tap before adding any flush chemicals. Also drive for 50 miles or so with the flush chemical in. Then two tap water flushes. Then the last flush distilled water. Refill with 70/30 mix. Always comes close to what I want, 50/50.

 

[Donald]

Once the cooling system is all mixed, drain some into a dixie cup and pop it into the freezer.

 

[901Memphis]

Originally Posted By: Donald
Once the cooling system is all mixed, drain some into a dixie cup and pop it into the freezer.


That's a cool idea, but better watch if you have kids around.

 

[SHOZ]

Or you could go get an antifreeze tester for a couple dollars.

 

[Colt45ws]

What I was trying to do is since Im diluting the coolant load down each time I use just plain water, was figure out the amount of concentrate needed to bring it back up to spec. So far I figured out that after one more drain and fill with water I will be at 78% fresh water with the remainder being the original load of 50/50. So, extrapolating (and this is where it gets fuzzy) my actual mix at that point would be about 90/10. Obviously, I cant just pour in 50/50 as that would leave me short a pretty significant amount. My actual requirement at that point to bring it back to spec is just over 2 gallons of concentrate. Since I cant put that much in the way Im draining and filling, I will end up short, less than a quart. About 55/45 mix. Not enough to worry about.
Thats if it I did it right. Im worthless at math so I likely screwed up somewhere.

 

[901Memphis]

Originally Posted By: Colt45ws
What I was trying to do is since Im diluting the coolant load down each time I use just plain water, was figure out the amount of concentrate needed to bring it back up to spec. So far I figured out that after one more drain and fill with water I will be at 78% fresh water with the remainder being the original load of 50/50. So, extrapolating (and this is where it gets fuzzy) my actual mix at that point would be about 90/10. Obviously, I cant just pour in 50/50 as that would leave me short a pretty significant amount. My actual requirement at that point to bring it back to spec is just over 2 gallons of concentrate. Since I cant put that much in the way Im draining and filling, I will end up short, less than a quart. About 55/45 mix. Not enough to worry about.
Thats if it I did it right. Im worthless at math so I likely screwed up somewhere.




You could just add the extra concentrate coolant you need into the system and leave it slightly over filled.

 

[doitmyself]

I don't think most caught on to what his concern is. Total system capacity is 4.75 gallons. He can only drain/fill 1.9 gallons out of the radiator. He needs to add 2.4+/- gallons of concentrate to get 50/50, ASSUMING that there is very little coolant left after all his flushes.

Is this a non pressurized overflow tank and could you add the extra half gallon of concentrate there and let it mix in as time goes on?

Maybe blow into the radiator opening (don't get poisoned) and push another quart of fluid out of the engine (don't laugh, just an out of the box suggestion).

You could add the 1.9 gallons of concentrate, run it a while, then remove some of the mix, and add a bit more concentrate to get closer. Wasteful, but still a solution.

That's the only ideas I have. I have found that coolant capacities are often way off, based on many years of changing vehicles and ag. equipment. I have a refractometer and it often shows only 40% up to over 60% coolant when I follow the mfg. capacity ratings.

That's just my experience. I'm satisfied to be between 45 and 55%.

In MY experience, some of the cheap testers are very inaccurate....again, just my experience with a particular Prestone needle type unit .

 

[TrevorS]

If you want to do this perfectly, then keep on flushing with distilled until you have 100% water.

Then drain and add 1.9 gallons of 100% coolant.

Then drive and then drain and fill 0.8 gallon coolant. This will give you 50:50.

If you do it after 2 flushes you have an 18:82 mix as your starting point.

One more drain and an add of 1.9 gallons of 100% coolant will give you a 51:49 mix.

 

[Sayjac]

Originally Posted By: doitmyself
.... In MY experience, some of the cheap testers are very inaccurate....again, just my experience with a particular Prestone needle type unit .

I found the same with a Deka needle type tester, in fact took it back to Napa for a refund after testing it on new Honda Type 2 in the jug.

But then I went to Wally and purchased an inexpensive ( Did multiple distilled d&f's till it ran clear, then same with Type2 till achieving correct concentration. Wasteful, but block drain is a massive pita and not at all practical. OP could do something similar, but using full strength AF it shouldn't take much to get to 50% as it did with premix.

 

[Colt45ws]

It difficult to drain just a little bit out, due to the radiator drain being broken off. Have to pull the lower hose.
Think Ill try my best off the info I have. Ill have to pick up a refractometer. I have one of those Prestone things, and yes, its junk. Within 5% is close enough for me. Even 10% down is probably okay, though a bit more margin would be better. I think it hit -10F overnight once in the decade Ive been here. It just doesn't get super cold here.

 

[Warstud]

You could always siphon some out of the rad itself and from the recovery tank.

 

[901Memphis]

If it has a pressurized tank you can always put a shop towel over the hole and blow extra out.