Antifreeze Concentrate VS 50/50 Mix
 

This summer I changed the water pump, hoses and flushed the cooling system. I replaced the coolant with Prestone 50/50 which is supposed to be good to -34. Always in the past I've just put in pure antifreeze in my other vehicles. No problems. Just the other day I tested the coolant and it says good till -10. What happened? Is the old plastic ball tester bad? The car will stay in an unheated, un-insulated attached garage all winter. Do I need to change it out? Now I hear someone say that pure antifreeze freezes faster and at lower temps than does 50/50. Is that true? Should I just leave it?

Re: Antifreeze Concentrate VS 50/50 Mix
 

Glycol coolant concentrate requires the addition of water to achieve the maximum or extended freeze protection, that is correct. It sounds a little strange but that's how it works.

If you've replaced the coolant in the system with a 50/50 mix I'd not worry about it, though maybe try a different tester.

Re: Antifreeze Concentrate VS 50/50 Mix
 

I avoid the premixed 50/50 like the plague. I like it stronger than that. You do need some water in it, for it to work. The problem with the 50/50 is the concentration falls rapidly with any water added. Heck change it. It's just not worth the risk of busting your block.

Besides, it always rubs me the wrong way paying more per ounce for less concentration / strength.

Re: Antifreeze Concentrate VS 50/50 Mix
 

Maybe drain a gallon and replace it with straight?

Re: Antifreeze Concentrate VS 50/50 Mix
 

70/30 is about as strong as a person needs to go even with the coldest temps but there are locations where this protection is needed. Folks that have good water need not purchase but one gallon to make 2-gallons of 50/50 mix. If the local water has too many minerals then a person has to get more creative or buy the 50/50. Good hydrometers are harder to find now days

When I was young, I would have never thought that folks would pay as much for water as they do now days. One way or another water isn't really free anyway but it cost a way lot less for community water back in the day and water wells didn't cost so much to drill either.

Re: Antifreeze Concentrate VS 50/50 Mix
 

Once you add water to antifreeze, it’s shelf life diminishes.

Re: Antifreeze Concentrate VS 50/50 Mix
 

This. Why pay more for water?

The floating balls method doesn't 'rise' to much accuracy, the number of balls floating just gives a step indication. There is no in between measurement. Also, let it stabilize for a few minutes, any micro bubbles clinging to a ball will give inaccurate readings.

Did you add any water during the summer?

Maximum protection is obtained somewhere around 70/30, but you don't need that unless you're in Alaska.

I'd say the easiest if you want to keep what you have, is to drain it into a bucket, and add full strength until you get the protection you want. Then top it off if needed with more of the correct ratio. It is a measuring game.

Re: Antifreeze Concentrate VS 50/50 Mix
 

Cat Man, Is your plastic ball tester an antique that was used for alcohol antifreeze? If you have any doubt, drain the coolant into an open bucket or tub and set it in the garage next the car. If it freezes then you know and the car engine will not be ruined because it will be empty of coolant.

Re: Antifreeze Concentrate VS 50/50 Mix
 

Last time I looked on the back of any bottle it said 50-50 gives the best protection, not 70-30 and certainly not 100%.

Antifreeze Concentrate
 

50/50 mix is easy to estimate and adequate for most climates but higher concentrations (up to a point) provides maximum freeze protection.

Re: Antifreeze Concentrate VS 50/50 Mix
 

I went 1 1/2 gallons of Prestone concentrate and the rest distilled water. Good to minus (-) 40. I live in Central TX. Never gets to that, but we were in single digit last February.

Re: Antifreeze Concentrate VS 50/50 Mix
 

There is an article in the most recent issue of V8 Times about this exact topic. The writer states that the 50/50 is better because of the quality of the water in it. "the company chemists have controlled the purity of the water to the best level for use in a cooling system." FWIW.

Re: Antifreeze Concentrate VS 50/50 Mix
 

There sure have been an awful lot of engine blocks turned to scrap metal overnight in "places that don't get that cold". Even if you live at the equator engine coolant is necessary for corrosion protection. It's a real shame, because erosion/corrosion (and running without a thermostat) can cause all sorts trouble. A 50/50 mix means not having to sweat it.

Draining the block isn't a guarantee to avoid damage, unless it can be certain it is drained completely.

Re: Antifreeze Concentrate VS 50/50 Mix
 

Last night I bought a new, swing dial tester from Walmart made by Prestone. I checked it and it's good to -34. So I guess that the old tester is bad and the car will be ok. Thanks all for the advice. Now I puzzle why my other vehicles, particularly my '55 Chevy with concentrated antifreeze never freeze up?

Re: Antifreeze Concentrate VS 50/50 Mix
 

They’ll get slushy you may not see it! Working on my sons car replacing radiator hoses in the cold our cotton gloves froze? maybe the water separated from the antifreeze

Re: Antifreeze Concentrate VS 50/50 Mix
 

It seems like people are under the impression that when the temp drops to whatever the protection is mixed to the coolant will turn into a solid block.That doesn't happen.It will slush.I worked for a contractor that took everything down to about zero to plus 5.He got into that habit during the mid 70's when antifreeze skyrocketed.It saved him a couple of drums a year back then,and he just stuck with it.I've worked around farm equipment,heavy equipment,and trucks all my life.I've never once seen anything freeze solid unless it had pure water in it.Well,once a few years ago I did see low-tox antifreeze freeze solid,we won't trust that stuff beyond one winter anymore.

Re: Antifreeze Concentrate VS 50/50 Mix
 

One of the coldest places I've had the displeasure to work in the winter was Craig, Colorado. That mountain valley can trap cold air in it for very long periods. It's not as much how cold it gets below freezing as it is about how long it stays below freezing in those -10 to -40 conditions. Working helicopters there near Craig was a beast. You can literally feel your eye balls start to hurt when trying to hot refuel a helicopter in those conditions. A person has to wear eye protection. The company I worked for had an engine failure the next season and I have always felt it was due to that cold exposure. After the turbine shuts down, you can hear all sorts of popping going on inside as the temperatures start to equalize.

I've seen 70/30 get slushy after a few days of -20. Liquid cooled aircraft engines like the Rolls-Royce Merlin have to use 70/30 due to the altitudes that they may have to fly in. It gets cold up there even in the summer time.

Re: Antifreeze Concentrate VS 50/50 Mix
 

I've read that a lot on the H.A.M.B. about the glycol antifreeze, "some" percentage is a whole lot better than none, that even fairly weak concentrations as a practical matter will provide protection from cracked blocks in below zero temperatures.

I have to wonder though, how the water pump or other other internals might handle slush or near icing? If it's all the same I only ever run a 50/50 solution and don't lose any sleep that way. The freeze protection never expires is my understanding, the anti-corrosion additives however get used up and it needs to be flushed and renewed for that reason. I like to be frugal, but whenever I get cheap, it ends up costing me money. There's a difference.

Re: Antifreeze Concentrate VS 50/50 Mix
 

I used to have a very good anti-freeze tester, it had a float w/letters, a thermometer which showed the temperature of the sample and a chart where one crossreferenced the float reading w/the temperature reading to get the freezing point of the sample. I had it so long all the rubber parts deteriorated to a point where it was no longer usable. Tried to find a good replacement, but no success. I don't trust the ones w/floating balls or any of the cheap ones which it seems is all one can get these days.

Here's a chart, courtesy of Detroit Diesel.

Re: Antifreeze Concentrate VS 50/50 Mix
 

Catman had it right. I'd drain 1 gallon of the 50-50 mix, then add 1 gallon of pure concentrate. Use the 50-50 you drained in something else.