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Which coolant? and Distilled or Ionised?

v6matt

Well-known member
Joined
10 Oct 2018
Messages
100
Hi All,

So my car is going in for a water pump change this week and I want to be sure that I am doing the right thing to top the coolant back off. (Apparently a water pump change will lose 1-2 litres)

1) Coolant - It seems either the Triple QX Red or Comma G30 is the right stuff for this. More Porsche specialists/parts suppliers seem to sell the Triple QX so will go with that

2) Distilled vs De-ionised - There is a difference between the two, but all the stuff in the UK or sold as battery water is de-ionised. What does everyone here use? If distilled, is there any easy to find source?

There are also pre-mixed versions of QX and G30 but there is no detail on what they mix the concentrate with. You would hope distilled but not worth the risk.
 
I expect mine is tap water. Can't see Porsche using anything else.
 
Im not going to offer an opinion just yet but i would like to hear a detailed reason why you need to use distilled water .

Facts please and not hear say as this has been mentioned before and id like to know the actual benifits over tap water .

Porsche specify 50 / 50 mix water antifreeze .

Fact finding for me :D
 
deMort said:
Im not going to offer an opinion just yet but i would like to hear a detailed reason why you need to use distilled water .

Facts please and not hear say as this has been mentioned before and id like to know the actual benifits over tap water .

Porsche specify 50 / 50 mix water antifreeze .

Fact finding for me :D

That's why I am here i.e for the facts. Fed up of all the bluster on other forums.

The chemistry behind it that normal tap water has minerals in it, these are said to be corrosive to certain metals. The distilled water removes these minerals and thus the perception it is better !

Sounds like porsche just use tap water (not even de-ionised with anti freeze?) Presumably what you use in the garage?

Lots of threads on here even e.g. http://911uk.com/viewtopic.php?p=893414
 
I am in no way qualified to comment fully on this but I am a chemist of sorts!

In terms of purified water there are 2 grades the first being distilled or RO water (reverse osmosis) this will remove the majority of the dissolved larger molecules from the supplied water (usually tap). This is done via the old method of distillation or the more modern day method of reverse osmosis. This is a process that involves a membrane with tiny holes in that only allow very small stuff through. Think of this process as removing the stuff that causes water spots on cars, scale in your kettle etc These molecules that are removed can be corrosive and to some extent usually are the level of which will depend on the water source in your area!

The next grade/ top grade is deionised distilled water this is the above that is then put through an Ion exchange process which takes everything (or nearly everything out) apart from the water H20 molecule. This process is an ion exchange resin where the positive and negative ions bind to the various beads (usually) in the cartridge. Water has no charge as it is neutral. You hear about acid rain causing erosion, this process will remove these corrosive ions from the water.

Detailers will always try to use rain water as this is usually soft with very limited molecules in it as it is derived from evaporation (think distillation), the only downside of this is that it may still carry charged ions which cause issues hence it is put through an ion exchange column to remove them.....

In terms of corrosion i would suggest that tap water is not likely to cause any problems, especially as it is mixed with antifreeze. Is Distilled or deionised any better - well yes but is it significant, i would very much doubt it.

Make some sense?
 
When I did mine after doing the water pump I used the premixed one from ECP and it was absolutely fine, biggest faf on was bleeding it and 'burping' the system through, as I did some of the coolant pipes as well which were weeping.
If your just topping up the system you won't need to do much.
 
Thanks all,

I have gone with the ECP Triple QX premix as the water in the area is very hard!

Only £6.99 for 5 litres delivered on ebay as well !
 
Water butt is nice and full at the moment, use some of that!
 
the missing factor here is that all tap water, whether in a so called soft water or hard water area contains Calcium in a compound form of Calcium and Oxygen, which will break down into calcium salts when the water is heated and especially when it boils (scale in kettles and washing machines). This will build up in radiators etc etc over time and cause them to lose efficiency.
Good old rain water is near to OK, but distilling water removes the calcium salts altogether, simply by being steam that cools down into water droplets and has no Calcium salts in it therefore.
That's my sixpeneth.
 
I understand the hard water / calcium but we are talking a 50/50 mix with antifreeze so approx 11 ltrs of each ..

Have there been any tests to determin the calcium content can actually cause issues ?

Porsche Dont specify we have to use distilled water on Any of their cars .. Afaik .. therefore my way of thinking is they dont consider it a problem.

Im not going to argue with anyone over this .. use what ever you are happy with .. but tap water is the cheapest by far .

Ive also never seen a blocked matrix due to Calcium in 14 years Porsche but also 37 years total .. no antifreeze and an old school cast iron block and you Will get rust though .. type of water wouldn,t really count .

Im just curious is all :)

Interesting answers though so thank you .

Richtw :thumb:
 
When I was doing mine I was just playing it safe and by using the genuine Porsche antifreeze and distilled water I decided it just couldn't get better than that for the cars sake and as I was draining totally and refilling using the special vacuum tool then I may as well give it the best possible chance of keeping cool efficiently. After all the coolant is supposed to be 'for life' ,now I don't believe that any fluid is for life but if it is changed every 5 years or so then it is worth it. Personally I have had to clean out clogged waterways in things like water heated enrichment valves on carburettors and such like, and to me it looked like limescale?
 

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