Hi guys, mind if I bounce one off you that borders of "dumb" question ?

Background:
I very seen many warnings not to ever use "stop leak" type products in these cars anytime ever. Apparently we have far too many small passages that could be plugged up. OK, that makes sense, no questions there, but it brings up an issue I've got to ask about before I mess things up.

I want to flush and replace the coolant in my 1998 XK8. what is bugging me is the fact that the well water at my house has very high mineral content. For example if I wash a pot and let it air dry, every where a few drops of water combine will leave a white hazy deposit after the water evaporates.

Thank God I can still buy Mister Clean Auto dry units on ebay (it provides highly filtered water to rinse) or I'd be pulling my hair out each time I wash the car.

My big concern is using an unfiltered hose to flush as per the excellent instructions on our site. Rather than creating internal cooling issues I wanted to ask. Is there much chance of the minerals in my tap water creating problems if I follow the instructions for a typical flush ?

I suppose a sealed cooling system does not provide anywhere or anyway for the minerals to precipitate, and they cannot cause issues while they are in suspension right?

I hope this wasn't a stupid question, I figured it is better to be sure. Thank You,

John

 

John. You may get other views, but my take would be that for a good flush through, your water and hose won't cause any problems.
However, once done and finally drained I would refill either with pre-mixed coolant, or if the concentrate - use de-ionised or distilled water to dilute.
Not sure what you can buy in the US - both are available here so I assume it's the same.
I think the problem with "stop leak" and "bar-leak" and suchlike is that they sort-of seek out little gaps and fill them full of expanded gloop. The X100 cooling system (and heating system) is designed to have many such little gaps, and glooping them up is not a good maintenance strategy !!

 

Thanks David, that makes sense mate. The more I think about it the more I realize that you need to take the mineral out of solution for them to collect. How could that happen ? Evaporation, electrolysis, osmotic barrier. Like you said given the amount of time a concentrated solution (hose water) is present in any significant quantity, there is very small chance of any significant accumulation. Thanks

 

If you're using the water just to flush, don't worry about it. It's long term where the problems will occur.

 

You can only drain about 40% of the total coolant volume, so there will be a significant quantity of well water in the system.

When I do a flush I use distilled water, it's not expensive and ten gallons won't break the bank. I fill and drain repeatedly, running the engine for a few minutes after each fill.

I then add the proper amount of concentrate to get to 50% and top off with water. On some cars I have not been able to add enough concentrate to get to 50% so I run the engine to get rid of air pockets, which sometimes requires driving.

That seems excessive, but my excuse is that I'm a chemist.

 

RJ. Maybe a little towards the over-cautious but we all probably err on the safe side of things.
I use the concentrate - flush through a couple of times with ordinary water and drain, then add the concentrate according to the total capacity. So - if total is 9.5 litres, I put in 50% concentrate (4.75 litres) then fill up with de-ionised water and then use that for any further necessary "topping up". I sleep fairly soundly having done that !!

 

RJ, Right now I wish you were a science fiction writer, secret agent, ballet dancer - hell anything without credentials like a chemist for this discussion 😉.

Looks like I'm going to pick up a few gallons of distilled water just to be safe. Mikey, David thanks for the info. You might be right but I m just going to play it real safe with this well water.

John

 

Sorry John, not trying to scare you, but with the risk of electrolysis and precipitates in the aluminum engine and radiator I tend to be cautious. If you flush four or five times and the fluid is pretty much clear and colorless there isn't much risk.

There have been places I have lived where I would just use tap water, but with the high mineral content of most well water it's better to be safe.

David- I recall from my trips to England almost 40 years ago one of the reasons given for the high quality of real ales was the excellent balance of minerals in the well water through most of the country. I do miss them, although the plethora of IPA's here does take the pain away.

 

John,

The only dumb question is one you don't ask.

The procedure I use is to drain, flush and fill with tap water twice (running up to temperature and allowing to cool again in between) then use de-ionised water 50/50 with coolant for the actual fill.

The tap water in my area is only slightly hard so this is adequate. If I lived in a real hard water area, I'd go with de-ionised for the intermediate flushes too. 10 or 20 litres of de-ionised water every 5 years is inconsequential next to the fuel costs in that same period!

Graham