Coolant

[monty]

Just how important do people think it is to use distilled, deionised or rainwater in the radiator rather than ordinary water from a tap? Is the water from a de-humidifier OK to use?

The reason I ask is that the workshop down the road had to drain my radiator to carry out a job & I suspect they have just topped it up with some Bluecol & ordinary tap water. Should I drain again & fill with either rainwater, distilled/deionised or from the dehumidifier or will it be ok for another year?

Cheers.

[Alec Pringle]

I shouldn't worry about it, just leave the current mix in there . . . . . . you can always run a can of water system cleaner through before the next antifreeze change.

 

Cheers

 

Alec

[stuart]

The only time I would ever worry is if the water is from a very hard water area and then only if you were going to leave it in for a long time. Down here the water is very soft so its fine for use straight from the tap (Kettles down here never fur up)

Stuart.

[RogerH]

Hi Monty,

if you look in a new kettle after boiling 4 pints of water there is no obvious trace of scale (calcium carbonate).

So your cooling system will live for a long time even with renewing the coolant every two or three years - dont forget the system never boils so the Calcium Carb may not come out.

 

You could use boiled water for the coolant as all the calcium carbonate would have been removed.

 

If you have a real concern you could run Calgon in the system every ten years or so but I think that would be overkill.

 

Roger

[boxofbits]

Agree with Stuart on that one, in that it is dependant upon geographical area.

 

Down here in Sussex our rain water filters through the chalk cliffs and surrounding downs, and we are always decalcifying kettles, sinks, coffee machines etc due to 'chalk' deposits.

 

However, I stripped my engine around 2 years ago and despite this, there was only some easily removed silty deposits around the liners.

 

Kevin

[Peter Cobbold]

The kettle furring test is a good one.

For the kettle-free with one of those new-fangled boiling water taps here's a map:

http://www.dwi.gov.uk/consumers/advice-leaflets/hardness_map.pdf

 

Peter

[MikeF]

There are two types of water hardness.. Temporary and permanent. The temporary will be dumped out by heating to boiling. The permanent can only be removed by distillation or de-ionizing. That's the (simplified) text book stuff. What this means in practice is that using hard water means you can only get a minuscule chalk deposit once. So it's not really a concern. If you have to keep topping up then eventually it could be a concern I suppose,but the concern then would be dilution of your anti freeze and it's protection against corrosion.Actually I think the main problem is accumulation of corrosion products clogging up over time. So I would suggest a one time de-clog and then fill with a proper water treatment/antifreeze, topping up if required with a water treatment mix, not just plain water. If you use rainwater or ice from defrosting fridge/ freezer/dehumidifier, or even one of those jug things in your mix it won't do any harm, but probably no measurable good. Interestingly and counter-intuitively very pure water can be quite corrosive, but the circumstances where that can happen are unlikely in our engines.

Mike

Edited August 14, 2016 by MikeF

[TR5tar]

I collect the water I pull from my dehumidifiers and use for such things as rad top up, car cleaning, and iron fill up. It's not that I think it's necessarily better, but at least it saves some money on the water meter, and being a bit tight I like that.

 

Darren

[peejay4A]

Bulk deionised water is surprisingly cheap.

[Lebro]

Rain water is cheaper !

 

Bob.

[Tom Fremont]

While we're on the topic, note that anti-freeze ( ethylene glycol ) is a very poor heat transfer medium, requiring approximately 4X the flow to carry away the same amount of heat as H2O.

 

So mixing in more than is required for frost protection is inadvisable .

 

Cheers,

Tom

[RogerH]

Hi Tom,

that is interesting. I thought EG conducted well. Well well you live and learn.

 

Roger

[MikeF]

While we're on the topic, note that anti-freeze ( ethylene glycol ) is a very poor heat transfer medium, requiring approximately 4X the flow to carry away the same amount of heat as H2O.

 

So mixing in more than is required for frost protection is inadvisable .

 

Cheers,

Tom

Hmmm that's interesting. There is more here http://www.engineeringtoolbox.com/ethylene-glycol-d_146.html

I imagine though the cooling capacity of any car will have been calculated for an antifreeze mix.

Mike

[Peter Cobbold]

Useful info on coolants here:

http://www.norosion.com/tech_coolant.htm

Peter

[PhilipB]

What about the wetting agents that are said to improve heat transfer, such as Millers Extra Cool and Redline Water Wetter? Are they effective?

 

Phil

[MikeF]

When this came up before I did a quick cursory read of the product claims and noted that they compared themselves to water, not antifreeze mix. Not a real comparison therefore. I concluded that claimed improvements were probably due to a reduction in surface tension (which would also be lower in a glycol/water mix). I recall there was more assertion than data, certainly no real world comparative stress tests like time to warm, time to cool down, running temperatures under extreme load or similar. So it wasn't clear why they should be "better" in some way. In the end I just thought even if they theoretically were better in some way, what would the practical benefit be? Possibly in a highly stressed competition setup there might be some. For normal use the present system is good enough, so how can it be bettered? IOW any notional improvement in thermal/physical properties would likely have no practical outcome. At best it would be like having a slightly more effective cooling pump.

 

Be interesting to know what serious competition types do.

 

Mike

 

(You can easily see the effect of reduced surface tension by putting straight water in your screen wash bottle and giving it a squirt, then put some screen wash mix in. The volume pumped increases.)