Distilled Water for Coolant Mix?

[Tinkerer]

Have noticed several folks replacing water pump, thermostat when replacing timing belt. Frequently as a preventive replacement.

Ya know, you can extend the life of the water pump (and the rest of the cooling system - e.g. thermostat etc.) by using distilled water for the mix when changing your coolant at the 30k interval.

Does anyone here use distilled water for their coolant mix?

For those that DO use distilled water and HAVE changed their coolant at the 30k intervals, has anyone replaced a water pump yet?

(I know, I know...it's not a scientific poll...but I'm just curious...)

 

[e9999]

??
I thought everybody here uses distilled or DI water?

 

[cabron]

you might want to make an actual poll to track your results

 

[donco]

Distilled water

I've been using only 50/50 distilled water/coolant in all my vehicles for years. Distilled water is slightly aggressive corsion-wise but I'm sure all the anti-corrosion additives in the coolant are more than sufficient to pacify it. Just to be sure, I put a couple teaspoons of baking soda in with it to neutralize it when doing a full flush.

Deionized water is more aggressive than distilled, so I don't use it. The worst thing to do where we live is to used tap water.

 

[LXPearl]

I have 217K on my 94 Toyota Previa on the original water pump. Always used the red Toyota coolant and distilled water. Changed the original hoses and thermostat a couple months ago as preventative maintenance. I am sold on the Toyota long life coolant - I even missed a couple changes (e.g. went 90K) and everything is going well.

Beware - Toyota dealerships are not as sold on the red coolant - they will put the green stuff in unless you reiterate repeatedly that you want the red. Obviously cost motivates their selection (or maybe they know there is little repair cost down the line with the red coolant).

 

[ZUREK]

Using only distilled or DI water can be very risky in colder climates (below 0C). Using coolant gives you more flexibility (freezing point ~ -60C). Also, any problems with boiling when using water alone? Some coolant will start boiling at ~135C versus water 100C.

 

[donco]

coolant issues

You don't want to be running 100% water anymore these days with a cast iron block, aluminum heads, aluminum coolant castings & aluminum radiator/heater cores -- serious dissimilar metal/galvanic action corrosion issues. In theory, water will cool just fine and can go way above 100C in a pressurized system using say a 12 or 15 lb cap. Actually pure water has better heat transfer properties than ethylene glycol and except for possible overheating issues, would be ok if corrosion weren't an issue, but anti-freeze does have better lubrication properties for the water pump longevity.

100% anti-freeze isn't good either and will have less sub-freezing protection than a 50/50 mix with water. The optimum mix is 60% anti-freeze/40% water. Check out this chart for various mix ratios:

http://www.gi.alaska.edu/ScienceForum/ASF6/680.html

If you're environmentally conscious, propylene glycol is more benign than ethylene glycol, but the downside to it is if you were ever to crack a head or blow a headgasket, and are running synthetic oil, once the oil is contaminated with propylene glycol, it turns to gel -- not good for bearings & cylinder walls & doesn't pump so well and the valve train will starve for oil.

 

[Tinkerer]

Ah, language - problematic at best, eh?

The thread Title: "....coolant mix.."

Emphasis: "mix"

I don't run 100% water, distilled or otherwise, for coolant mix.

Per common wisdom & OE recommendations, I run about 60/40, ethylene glycol coolant / distilled water.

BTW, ethylene glycol is not a significant problem environmentally, if you dispose of the stuff in your backyard or front gutter: It breaks down within a few days to harmless byproducts, upon environmental exposure. See

http://www.atsdr.cdc.gov/tfacts96.html

Just make sure your favorite mammal doesn't ingest it within a few days. (Dogs love the taste, I've heard...)

 

[donco]

BTW, ethylene glycol is not a significant problem environmentally, if you dispose of the stuff in your backyard or front gutter: It breaks down within a few days to harmless byproducts, upon environmental exposure. See

http://www.atsdr.cdc.gov/tfacts96.html

Just make sure your favorite mammal doesn't ingest it within a few days. (Dogs love the taste, I've heard...)

Thanks for posting that link! Just be sure the granola eatin greenies don't hear us talk like that. I did similar research on that too when the neighbors started giving me grief over winterizing my boat in the back yard. There is no evidence any left over ethylene glycol has any impact when released into lake water either, but mine is always flushed at home when taking it out of its winter slumber, before the 1st trip to the lake in the spring.

Our illustriuous mayer passed an ordinance a few years ago requiring all antifreeze sold within the county to have a bittering agent to deter animal ingestion -- d*mn, gotta find another way to get rid of strays now.

 

[NMuzj100]

I think distilled water for the mix is a no brainer. 50 cents a gallon at the stuff-mart.

 

[Tinkerer]

Agreed, distilled water for coolant mix is a no-brainer. But many people don't think about using it. Back in ancient times (when I spun a wrench for pay) we would hook a hose to the city water spigot and rock & roll with whatever came out of the tap plus Prestone. I'd say that's probably the most common method nowadays too.

 

[rph74]

I use tap water to flush the coolant. I flush the old fashioned way-Drain coolant, add water, run motor for 5-7 minutes. Drain again and repeat 4 times or so.

I use distilled water for the final filling though.

Any idea if the tap water used in flushing makes much difference here?

 

[Tinkerer]

Pardon the verbosity below (it's morning and the coffee just kicked in).

Flushing:

1. If you always use distilled water for the water/EG mix, change every 30k miles, and the vehicle system is well-made (as with the 100), reason #1 to flush is negated. (Corrosion & byproducts are essentially nonexistent)

2. When you drain coolant from the 100, you drain about 90 to 95% of the coolant out.

This means:

Since you've been using distilled water & EG at 30k intervals in a well-made system, the 5% of coolant left in the system is still very clean & chemically friendly to the system anyway.

Diluting 5% residual old (but still "clean") coolant with 95% fresh coolant yields a net solution that is so close to a 100% fresh solution that it is "close enough for all practical purposes" (to borrow the phase).

(Mainly, you want to restore the anti-corrosive & lubricative properties of the coolant, and 95% new stuff will do this just fine.)

3. If you flush, that 5% residual left in the system will be tap water, after flushing. (Unless you use special equpment to evacuate & fill...and even that equipment leaves some residual.)

3a. You didn't have to flush at all, if you've been using distilled water & EG at 30k intervals in a 100, because there's no corrosion byproducts in the system to flush, and all coolant passages are still spotless & free-flowing.

3b. The 5% residual tap water in the system after flushing will contaminate the system with the stuff in the tap water. Depending on the water contaminants, this could be enough to start the downhill slide of increased corrosion & etc. in the system.

(Remember, coolant system corrosion is another sort of "system cancer" that can start a chain of interacting conditions that snowball to eventually bring down the system. Better to avoid entirely from Day 1. Ounce of Prevention vs. a Pound of Cure, and all that.)

IMO, flushing not required, not recommended, unless the system really NEEDS flushing - e.g. to get corrosion results out and clean passages. In that case, a true chemical flush is required.