Skip to main content ↑ ↓
Topic: Coolant - Tap, Distilled or de-ionised (Read 1167 times) previous topic - next topic

Coolant - Tap, Distilled or de-ionised

Hi,

What's your potion for Coolant :) I've used tap for top ups and distilled for refreshes. Don't know what the ideal is and read all sorts on the internet.

There is a 4th option actually - Comma ready-mixed

Re: Coolant - Tap, Distilled or de-ionised

Reply #2 –
So is tumble dryer water ;)
Mk2 Driver
Mk2 Silver 8v
Corrado G60 Turbo
Mk2 Red 8v
Mk2 Grey 16v
Mk2 BBM ABF
Bora 20vt
Mk2 Green VR6
Mk2 Green ABF
Mk2 BBM 20vt
3.2 TT Roadster
Mk2 Red 16v
225 TT Coup
3.2 TT Coup
Mk4 Anniversary
Mk7 Red GTI Performance
Mk2 Red GTI Restoration
Mk2 BBM R32
911 Carrera 4S

Re: Coolant - Tap, Distilled or de-ionised

Reply #3 –
Quote from: Monkey on
So is tumble dryer water ;)

Funnily enough we just got one of them too. I've never had one, but the work we had done on the house last year has allowed us the luxury of a utility area.

I only ever pay for ready mixed coolant for motorbikes, it's expensive per litre, but due to the higher use of alloys and the smaller amount required it's easier to let someone else deal with the science and get the mix 100% correct plus it's usually a really cool luminescent colour. For a car I'm happy to go 50:50 using de-ionised or distilled.

Re: Coolant - Tap, Distilled or de-ionised

Reply #4 –
So defintely not water then! I've been looking at the premixed stuff but a bit pricey. I need loads of it as at least 4 cars need coolant changes. Probably should stop buying them. I think I have now. It's just I moved house and rather than 2 spaces I have space for 6-8 soo...

Re: Coolant - Tap, Distilled or de-ionised

Reply #5 –
Tap water contains many contaminants, especially here in the south west where our water is so hard. The chemical reactions of the different metals within the engine combined with the heating and cooling isn't the best ...  I didn't do Chemistry at school and failed Physics so I won't go into the science. But it's best avoided.

That said, in the good old says no one gave a toss about stuff like this. Whether through ignorance I don't really know, I guess that's why changing the fluids was recommended for every 2 years, and some of the modern pre-mixed coolants are apparently 'lifetime'.  If you use tap water I'd certainly flush more regularly.

Re: Coolant - Tap, Distilled or de-ionised

Reply #6 –
I used to work in the water industry and it's really aggressive, it'll leach any minerals it can until it's reached an equilibrium (hence the term mineral water).  When you see people get electrocuted in the movies, it's not the water conducting the electricity, it's the metals in it.
I made RO (reverse osmosis) units, they essentially make pure water, you can't drink it, or pump it though copper, as pure water would eat it!

A friend has an E39 M5 that has only ever seen DI water and BMW coolant, we changed the water pump on it and the insides of the pipes were like brand new!
Mk2 Driver
Mk2 Silver 8v
Corrado G60 Turbo
Mk2 Red 8v
Mk2 Grey 16v
Mk2 BBM ABF
Bora 20vt
Mk2 Green VR6
Mk2 Green ABF
Mk2 BBM 20vt
3.2 TT Roadster
Mk2 Red 16v
225 TT Coup
3.2 TT Coup
Mk4 Anniversary
Mk7 Red GTI Performance
Mk2 Red GTI Restoration
Mk2 BBM R32
911 Carrera 4S

Re: Coolant - Tap, Distilled or de-ionised

Reply #7 –
De-ionised it for me then! Good to hear the insight as haven't had a straight answer in the past. Before I confident working with cars my mechanic said "just top it up with water" which I thought was a bit odd.

Re: Coolant - Tap, Distilled or de-ionised

Reply #8 –
Quote from: MJA on
De-ionised it for me then! Good to hear the insight as haven't had a straight answer in the past. Before I confident working with cars my mechanic said "just top it up with water" which I thought was a bit odd.

Ask the mechanic what he puts in his car, not how he treats customers cars ;-)


I always ask any tradesmen what would you do if it was yours rather than ask what should I do?
You can see the turmoil in their face sometimes as that’s not the question they were expecting lol
 

Re: Coolant - Tap, Distilled or de-ionised

Reply #9 –
its supposed to be distilled water,but as i think mentioned before, as long as still mixed with correct antifreeze the properties of the antifreeze are such that they mitigate the tap water issues.
Just general maintenance and regular  coolant changes  i change coolant every 2 years, which is draining out, flushing with tap water until clear, opening heater matrix lines and trying to flush that out too.  then refit hoses. mix 6 litres of antifreeze and distilled water at local climate conditions.. (cold countries 75% + coolant, uk can be less than 50% since we don't actually get to minus 20c)

Have seen people recommending flushing coolant system with BIO WASHING powder, add in to tank and running with water until boiling cool,then heat up again, then flush out..... not done this myself so cant say if works.