Distilled water/ de-ionised water?

[chan61922]

Hi guys forgive my stupidity, but my coolant needs a slight top up, about a cm below min mark atm confirmed checking car once cold first thing in the morning, I’m hoping to pick some coolant up from dealer today hopefully, I beleive the coolant comes in concentrate form so will need a 50:50 mix? Or should I do a diff ratio, or for a top up do I even need to water down? Either way is distilled water the same as de-ionised water? Can’t find any of the usual high street names that stock distilled, where are people sourcing it from? Bonus question is g12 coolant okay to mix with g13? The header tank states g13 but when I spoke to dealer on Friday he reckon they gone back to g12 again, I thought g13 was the successor of g12... hmmm

Any thoughts appreciated many thanks

[trickywoo]

For such a small amount put tap in.

De-ionised isn’t a good idea as it will re ionise and distilled becomes acidic when exposed to air (more specifically carbon dioxide).

I always try to use premix for these reasons.

[chan61922]

Thanks bud, wasn’t aware distilled becoming acidic in open air, surely tap water can’t be great either with all the additives etc I also live in a hard water area, I don’t even drink tap water myself. I’m thinking 100ml give or take will do the trick, I’ll just top up to between the min - max mark as it’s in a pressurised tank, surely be safer to just go neat?

[trickywoo]

Yes, hard water tap isn’t great either.

Try and get some premix if you can.

Prestone do a multi compatible premix.

[chan61922]

Perhaps I’ll just get another brand of compatible g13 pre mix from ECP/Halfords etc. I’m abit an@l about what I put in my pride and joy lol

[kambites]

I use distilled water (from my garage dehumidifier) for top-ups. I wouldn't even bother putting antifreeze in for such a tiny addition; no garage ever measures the proportions that accurately when changing the coolant anyway.

[chan61922]

Thanks problem is I don’t have a dehumidifier nor do I know where to source distilled from lol there’s eBay and Amazon etc but I don’t trust them for 2 things, car parts and food :/

[kambites]

Tumble drier? That's basically a dehumidifier.

[Fonzey]

If you've already bought coolant, for such a small amount - just put it in neat.

[kambites]

Fonzey said:

If you've already bought coolant, for such a small amount - just put it in neat.

Yeah that obviously works too!

[chan61922]

Blimey don’t like the sound of that using water from washing machine haha. I’ve managed to pick up some today from dealer and it’s pre-mixed so I’ll just top up with a trickle of that, many thanks for help guys

[lowdrag]

I have a dehumidifier in the garage linked to a water bottle. I just change the bottle and SWMBO uses it for the ironing. I've never bothered to worry about what water to use for topping up the radiator, and in 38 years the E-type has never had a radiator problem.

[AW10]

BMW gives a spec for the water to be used for mixing with their coolant and I should think that any tap water in the western world will meet the spec just fine. De-ionised/distilled water is an OTT expense if you have to buy it.