Frozen anti-freeze....

Just an observation here which made me wonder... I changed my stat about 3 weeks ago and being a lazy fekker, I haven't got round to disposing of the tub of coolant sitting in the corner of my drive. Now it's been generally very cold here since then. Last few nights have been below freezing with a few -6c's in there. Strangely, there is a fairly thick layer of ice in the tub of coolant! It's a 50/50 mix of halfords OAT. I can only assume that the mix has separated with the water on top. What I was wondering is, if (for example) you have a car sitting idle for a couple of weeks in sub zero temps, this could happen inside the engine. Potentially you think the car is protected, but there could be ice in the top of the cooling system. It would make sense therefore, if you have a car not being used in extended cold weather, to run the engine every couple of days to keep the coolant mixed. I suppose we don't usually have to worry about it in this country very often but it's probably worth noting.

One question,

Have you tested the antifreeze to see what mixture it is?
You can always test by putting in your home freezer to check it.

Cheers

neilly said:

One question,

Have you tested the antifreeze to see what mixture it is?
You can always test by putting in your home freezer to check it.

Cheers

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It's 50/50. Only been in there about 6 months and topped up as required with a 50/50 mix
I know it is as I mixed it myself.

Bobdog said:

It's 50/50. Only been in there about 6 months and topped up as required with a 50/50 mix
I know it is as I mixed it myself.

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Is it an open tub and has it been raining since you did it? Rainwater could have diluted it

Kwakerman said:

Is it an open tub and has it been raining since you did it? Rainwater could have diluted it

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Yes it has but not much. I did wonder if the rainwater could sit on top of the coolant if it was undisturbed but it should be soluble and mix out anyway.

Are you sure you topped up with 50/50 mix? (Are you sure it wasn't 50/50 pre-mix that you then diluted?)

GRATCH said:

Are you sure you topped up with 50/50 mix? (Are you sure it wasn't 50/50 pre-mix that you then diluted?)

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Erm no. I never buy pre-mix. I've always got 2 5 litre containers on the go, to mix the concentrate 50/50. Pre- mix is a rip off. You're paying about £8 (in halfords) for 2.5 litres of water!

Just had to go and look at my coolent after seeing this thread
My disco has been standing for four weeks so went and had a look, and the coolent is still fluid so no issues there, even though there's some ice underneath the bonnet.
I've been using Halfords OAT antifreeze for fifteen years now, and now due for replacement later this year, alway a summer job, and being five years since I last replaced the stuff.

Can't say why coolent at a 50 50 concentration would freeze.

Got to be rain or dog ****

Maybe it was rainwater just sitting on top, though we haven't really had much. Its supposed to be -5c again tonight so im going to mix it up in the tub and see what happens.
-just been to mix it and had to break the 3/4 inch thick slab of ice first! Weird...

Bobdog said:

Erm no. I never buy pre-mix. I've always got 2 5 litre containers on the go, to mix the concentrate 50/50. Pre- mix is a rip off. You're paying about £8 (in halfords) for 2.5 litres of water!

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True but when you get to my age, for what little I use, it's worth it to avoid all the faff & I use Halfrauds (-8 degees) all year round.

norseman said:

True but when you get to my age, for what little I use, it's worth it to avoid all the faff & I use Halfrauds (-8 degees) all year round.

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Lol mine's been changed 3 times in the past year! New rad, new water pump and new thermostat!

You have got me at it now
I haven't tested my antifreeze since I replaced it over 4 years ago, so I'v been out again and tested the concentration of mine with my little Halfords tester, it show ok to -24 with the four colour balls at the top, that's the lowest scale the tester has but that will do for me.
I have a larger professional style tester which has a lower scale so I use that also, and that shows in between -35 & -40, that will do.

discool said:

You have got me at it now
I haven't tested my antifreeze since I replaced it over 4 years ago, so I'v been out again and tested the concentration of mine with my little Halfords tester, it show ok to -24 with the four colour balls at the top, that's the lowest scale the tester has but that will do for me.
I have a larger professional style tester which has a lower scale so I use that also, and that shows in between -35 & -40, that will do.

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Maybe there's some scientific reason like it wont freeze when its enclosed or that being in an open tub allows water to sit on top then freeze.

Ummm

Wind chill might take your -6C down to about -10 or so. Also the smaller the quantity the higher the freezing point. Unless you get down to about -15C for an extended period,(as we did a few years back) I wouldn't be worrying. More danger of the diesel waxing than the engine freezing!