Distilled water for your cooling system

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I use the Prestone flush kit (where you put a plastic tee in the heater hose and sttach your graden hose to it for a good flush), which I think works great.

I also think that using distilled water only is a great idea. However, for the life of me I have never been able to get a car's cooling system to completely drain, so that I could start fresh with only distilled water. What I end up doing is after the water has been coming out clear for a while, I let it drain out of the petcock until it's not draining any more. Then I add half the coolign system capacity in A/F and top off with H2O. I've run into several instances where I couldn't even get the full amount of A/F in there, even once the T-stat opened, and I basically filled up the overflow with pure A/F knowing that it will eventually mix in over a couple of driving cycles.

So my question is, how do you drain a system bone dry to use pure distilled water?
 
Even after finding and removing block plugs and the lower radiator hose, I have never been able to add back what the owners manual says the system holds. In a tight system, as long as you go from coolant change to coolant change without adding very much, a little of the worst tap water won't hurt. If you really wanted too, I guess you could flush, drain, refill with distilled water, run engine, then drain as best you can again, and correct amount of pure, new antifreeze, and top off with the distilled water.
 
I heard a while ago that Mercedes said not to use distilled water because it would pull minerals from the block to make up for it. I don't know if this is true. I am using half distilled and half 50 cent a gallon spring water, the tap water here is horribly hard.
 
Maybe you could do your regular flush using the kit\garden hose like you're doing now then after that continue with the flush using 2-3 gallons of distilled water. I wonder if that will remove the non-distilled water and replace it with just distilled. Then you can top it off with anti-freeze and check your boiling\freezng point with that handy plastic tester. Not sure if it's a good idea to run the system dry. I would think it would damage the water pump by going dry? Maybe not sure. Idealy I think the only way to totally flush the system dry would be to remove lower rad hose, flush system with water using a flush kit, leave engine running without adding anymore water then shut off the engine when there's no more water coming out. But again I never did that and not sure if running the system dry like that even if it's for a few mintes would have adverse effects on the water pump.

[ May 21, 2004, 10:14 AM: Message edited by: jeepzj ]
 
On most engines, once you remove the lower radiator hose, the water pump drains. Running the engine with it dry is much more likely to damage the water pump than pump any water out. The water pumps I have changed have varied from being a PITA to being an awful PITA. With RWD, sometimes they take the radiator core with them when they go.
 
If you want to save a few cents, use the drain water from your house air conditioner or dehumidifier. This is essentially distilled water and has no minerals in it. It might have some airborne dust particles in it, but that's not a problem. Since it's free, you don't mind wasting this in a final flush of your system.
 
I also have a Prestone kit, and have wrestled with this problem myself - so far without reaching a solution I am completely happy with.

What I'm thinking about doing next time I flush the cooling system is this: Purchase several ("several" will be defined more precisely sometime between now and then) gallons of distilled water. Modify some kind of multi-gallon-capacity water dispensing bottle (that comes with a spigot) to attach to a length of garden hose. Set that bottle up on a ladder or something near the vehicle, filled with the distilled water.

I would now have (if the container is high enough to get decent pressure head) what amounts to being a distilled water faucet. I'd perform the flush using the kit pretty much as normal, and when I was done I'd wind up with the cooling system filled with pure distilled water.

After that, the usual: drain the radiator; fill with half the nominal system capacity of pure coolant; top off with distilled water.

This sounds great in my head (famous last words), but I have not tried it yet. Nor will I for another year or so, barring unforseen circumstances, so I guess I have plenty of time to ponder it.
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quote:

TAP WATER IS BAD, DISTILLED WATER IS BETTER, BUT DEMINERIZED WATER IS THE BEST

LOL, Distilled water is water that has been demineralized using a distillation process. Generally, demineralized indicates that it was demineralized via some other process beside distillation.
 
Brad, I think you're onto something. Here's my suggestion if you really want to get serious.

1 - Use the garden hose and completely flush and clean the system as normal.
2 - Disconnect both radiator hoses at the radiator side to completely drain the radiator and most of the engine block.
3 - Disconnect both heater hoses. Pour a gallon of distilled through one of the hoses (the upper one, if applicable), then blow it out with compressed air (optional).
4 - Pour a few gallons of distilled through the upper radiator hose into the engine block. This will result in 100% distilled in the engine block, which is where almost all of the fluid sits that you can't get out.
5 - If you really want to go nuts, block off the bottom radiator outlet, fill it will distilled, then drain it. This is probably not necessary, though, as it should be drained completely, anyway, when you removed the hoses.
6 - Put it all together, pour in half the system's full capacity of coolant, then top off with distilled.

By the time you're done, you'll have 99.99999999% coolant/distilled water, with the rest tap water. I don't know of any other way, except if your block has a drain plug, which most don't, to get it better than that.
 
quote:

Originally posted by rgl:
I heard a while ago that Mercedes said not to use distilled water because it would pull minerals from the block to make up for it. I don't know if this is true. I am using half distilled and half 50 cent a gallon spring water, the tap water here is horribly hard.

About 25-30 years ago, my Dad had a Toyota Celica 4-cylinder. He liked to add in tap water whenever the coolant level got a little low. After about 10 years of tap water top-off's, one day the cooling system fails. When the shop opens the thing up for a look-see, we see that all the water passages are blocked by a furry white, table-salt lookalike material. From that day on, only 2 things go into my cooling system: antifreeze and distilled water.
 
If you are religious about your maintenance, and it definetly sounds like you are, I wouldn't sweat it either way. I've done both routes, but now prefer the drain and fill with antifreeze/distilled water method.

While this is only replacing a portion of the whole capacity, I feel that I'm safe given that I do this once a year (roughly 20K miles).
 
Distilled water is not necessarly demineralized. Demineralized will say so on the container. In the lab we could either specify either demineralized or distilled. ed
 
quote:

Originally posted by Eddie:
Distilled water is not necessarly demineralized. Demineralized will say so on the container. In the lab we could either specify either demineralized or distilled. ed

How do you distill water and end up with minerals in it? And why would anyone?
 
Water can be demineralized by distilling, deionization, or reverse osmosis. The final amount of minerals may be more dependent on the materials of the apparatus used and the storage container. Water is quick to contaminate itself with minerals from what ever it is in contact with. Plastic is more resistant to this than metals or glass. Any of the processes will produce water that will work fine in all but the most exacting laboratory process as well as in your radiator. As long as you do not have to top up much between changes, all but the worst tap water will do.

I have not had the cap off the tank on my 02, 40K Cavalier yet. I am over due on changing the antifreeze in my truck, but don't remember adding anything to it. I have 2 gallons of Prestone Low Tox, and it is on the list. If you are adding very much, I would do a UOA, and if it has antifreeze in it, trade it before your are stuck with a head gasket change.
 
See thread on coolant flush posted by Oldwagon (page one or so); see first post by Jelly.

I hadn't tried this method since before the fall of Saigon . . . cause it takes forever, but boy does it work!

We have a Jeep Cherokee (XJ; 242 cid 6-cylinder) with its little bitty capacity system that -- even with [2] changes prior to the last (at about 58k) -- the outlined method got stuff out even up to the end of the final flush. Much more than the usual tee and garden hose OR the dealers powered machine. Think I used about 13-14 gallons of distilled water, or 3 to 4-gls per gallon of capacity, total; drove several hundred miles in about four days to allow system to cycle cold::hot quite a few times. (Normal business days).

Did this in winter. Heater core warmed noticeably faster than before (just like new).

First change: at three months since new delivery; after first summer. (Dealer coolant change).

Second change: one year later; including new hoses and dealer power flush.

Third change: (as above) 1.5 years later; vehicle gone thru [3] of our seven-month summers.

Refilled with Xerex G-05 and proper amount of SCHAEFFERS "Clean and Cool" (had been using it before with "green" (spec'd) coolant); owner pre-mix to 50-50 prior to filling.

Ph always checked.
 
I too have been plauged for ages in this issue of using distilled water in the radiator, since I have a reverse Osmosis filter system installed in my house I have been using water from the filter for my radiator.

Thankfully Castrol in India has solved the problem for me by marketing 50:50 readymix coolant which comes from the factory with demineralised water and coolant. Not only is the issue of using proper water is solved, the ratio issue is also easier now as all you have to do is fill up the radiator to get a proper mix.
 
quote:

Originally posted by Eddie:
Distilled water is not necessarly demineralized. Demineralized will say so on the container. In the lab we could either specify either demineralized or distilled. ed

Distilling involves boiling the water so that the H20 departs as steam, leaving all dissolved material, including minerals, behind in the vessel in which the water was boiled. Then, the water vapor is run through a condenser in which it is cooled, returned to a liquid state, and collected in a different container. So how do you conclude it could then have minerals in it? I'm not in any way trying to sound snotty about this; I'm just hoping I didn't miss some lesson in 7th grade science and I've been mistaken for the last thirty-something years about the process of distillation.
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