distilled water cooling how long?

[er9]

curious...how long can I leave only distilled water in cooling system?

to explain. i just finished completely overhauling my entire raw and fresh water cooling systems. I wanted to do this before I tackle rebuilding my cylinder head. instead of wasting anti freeze I just filled the fresh water side with distilled water to check all is good. in a couple of weeks I will replace my injectors and a couple weeks after th at start taking the cylinder head off for rebuild.

when I start to pull the head I will have to drain the fresh water side again so didnt want to waste antifreeze. can I leave the fresh water side filled with just pure distilled water for a few weeks with no issues? I wasnt sure if pure water might introduce immediate corrosion?

[a64pilot]

I wouldn’t leave it in there for more than a day or two myself without antifreeze, but then I go overboard taking care of that $$$ engine.

There isn’t much if any difference in corrosion between drinking water and distilled water, it’s actually the oxygen in the water that causes corrosion.
In fact if you fill a 55 gl drum with water and seal it, it will rust just a little until the O2 is consumed, then stop, no matter how many years it sits as long as it’s sealed it will not rust on the inside.

A few weeks won’t kill it, but there will be some significant rust, drop $10 on cheap antifreeze and inhibit it.

If money is that tight, then drain all the water out of it and leave it dry is much better than leaving pure water in it.

[Jim Cate]

Why can't you capture the antifreeze when you drain it out and then put it back in? I do this routinely when servicing the FW side of the system.

Jim

[thinwater]

The AF does not need to be full strength to help with corrosion. Even a 10% "dash" will slow corrosion by an order of magnitude. A single dollar can make a difference. Additionally, the last AF left a pasivating film; switching to distilled water only can strip that film, resulting in irregular passivation going forward.


Seems obvious to me.



(In a former job I tested coolants and developed formulations)

[Wotname]

Assuming a cast iron engine and head, I won't sweat it too much. Back in the day, tap water was all that was used and engines didn't corrode away in a few weeks (or years for that matter).

However if you have significant alloy components (or expect slow freezing ambient temps) then yes, any coolant additive is a good idea.

IMO.

What engine???

[RaymondR]

Boiling water is usually enough to get the oxygen out, won't do anything for galvanic corrosion though.

[roverhi]

2nd Wotname. We used to drain out the antifreeze and replace with tap water at the end of winter. Most engines were all cast-iron and didn't seem to suffer. Raw water cooling for boat engines was/is pretty much standard on boat engines on the lakes.

Back when the Volcano was going off here on the Big Island and spewing sulphur compounds 24/7/305760 did make the mistake of using catchment water in a newly rebuilt motor. The steel freeze plugs rusted out after a month or two. Replaced the steel freeze plugs with copper used premixed straight coolant and engine still running 20 years later. Be careful if you are around an active volcano.

[er9]

Hey thanks for all the great replies.

I wasn't trying to cheap out on my engine or anything i just knew i would only be filling the fresh water side just long enough to run the engine up to temp to test the new thermostat, and all the hose connections under heat and pressure.

i knew i would be draining it shortly thereafter so it just seemed like a waste. that and the fact that draining the fresh water side on my engine guarantees coolant all over the engine. i had to bathe my engine in fresh water the last time i drained it.

i did run it up to temp (160) and got to test everything, all is good so i will probably drain it tomorrow but at least now im not all freaked out im going to rust it overnight.

by the way its cast iron engine...

[er9]

Originally Posted by roverhi

2nd Wotname. We used to drain out the antifreeze and replace with tap water at the end of winter. Most engines were all cast-iron and didn't seem to suffer. Raw water cooling for boat engines was/is pretty much standard on boat engines on the lakes.

Back when the Volcano was going off here on the Big Island and spewing sulphur compounds 24/7/305760 did make the mistake of using catchment water in a newly rebuilt motor. The steel freeze plugs rusted out after a month or two. Replaced the steel freeze plugs with copper used premixed straight coolant and engine still running 20 years later. Be careful if you are around an active volcano.

wow! who would have thought? im not sure i like volcano's anymore.

[Jim Cate]

ER, may I humbly suggest that you change whatever fitting(s) you have for draining the coolant to some that incorporate hose barbs so that you not only can avoid the mess that you desribe, but that you can direct the exhausted coolant into a container for re-use.

Jim

[er9]

Originally Posted by Jim Cate

ER, may I humbly suggest that you change whatever fitting(s) you have for draining the coolant to some that incorporate hose barbs so that you not only can avoid the mess that you desribe, but that you can direct the exhausted coolant into a container for re-use.

Jim

thanks Jim. yeah i didnt think of that, good idea. i think when i take the head off and i have much better access i will try and get one plumbed into the return line.

[thinwater]

Originally Posted by Jim Cate

ER, may I humbly suggest that you change whatever fitting(s) you have for draining the coolant to some that incorporate hose barbs so that you not only can avoid the mess that you desribe, but that you can direct the exhausted coolant into a container for re-use.

Jim

Adding fittings for winterizing and coolant changes is ALWAYS time well spent. You will thank yourself at the change of the seasons! It makes it so much easier and more pleasant. The next owner will thank you too!

[blubaju]

distilled water is particularly corrosive. With no minerals to give the water pH balance, distilled water acts like a magnet, absorbing chemicals from plastics, nickel from stainless steel, aluminum from aluminum containers, and carbon dioxide from the air. Topping up with destilled water is ok, because it is clean, but never ever fill a complete charge without some anticorrosion-additive!

[Djarraluda]

As an aside to the actual query:
Antifreeze is typically Ethylene Glycol plus corrosion inhibitor. The inhibitor is critical because the glycol breaks down due to oxidation. OK, some will be Propylene Glycol, but most are Ethylene as it is cheaper - NEVER mix the two, it turns into jellyfish like tentacles that gum-up all the cooling passages.
The corrosion inhibitor will be chosen to also limit corrosion with either aluminium or cast iron and sometimes for combinations thereof, thus part of the choice of particular brand names for different engines.

To preserve the life of the glycol, limit the aeration during drain and refill operations, the less oxygen mixed in, the less it decomposes and longer it all lasts.

You are good to avoid wasting the antifreeze, both for cost and environmental issues, even the 96 hrs to degrade will harm enough life in the water and if ingested direct will lead to liver damage etc.

Roger