Engine Coolant and Storage After Shows

[Daniel Williams]

I finished a Bruce Macbeth engine about a year ago. I ran it at Cabin Fever this year. I used Water Wetter as an additive to distilled water for the coolant. I left the coolant in the engine afterwards, thinking that the Water Wetter would keep corrosion at bay. WRONG! This pasty white stuff seeped out of a couple unions, and turned my brass water tower green with corrosion. I have brass, copper and steel being exposed to coolant. After this lousy discovery, I ran the system pump using vinegar, emptied, used distilled water to clean the system afterwards, and then ran denatured alcohol in the system to remove any remaining water and force air dried the whole works. What do you folks use for coolant, and what do you do about storage after running it at a show?
Thanks,
Dan

 

[GreenTwin]

I learned the hard way years ago that any steam engine that is run on steam, and then not dewatered, will be locked up solid the next time you want to run it.

I use a lot of WD40 to displace the water inside of steam engines after a run, even if I am running on air, since air has moisture in it.

I am not sure if WD40 would be appropriate in a coolant system or not, but it is great about driving out the water and stopping corrosion.

.

 

[gbritnell]

I have had the same coolant in my engines for years with no problems. 50/50 water and antifreeze.

 

[ChazzC]

Using distilled water in cooling systems always starts a debate. One side says it prevents hard water calcification. The other is that distilled water is “hungry” and can promote corrosion in systems with dissimilar metals [hungry water was discussed at length by The Tappet Brothers, Click & Clack, one of whom said that a professor had written a long letter to him about it].

@gbritnell is one example, and @Daniel Williams is on the other side. I would try a middle position and recommend using softened water, but not too soft (had experience with a hot water circulating system a few years ago that was running a softener in the loop with steel pipe and it blocked almost solid after less than a year. The water was used for cleaning in a food plant so couldn’t use any chemical treatment so the system was redesigned and all of the piping replaced with Copper.

 

[colby15642]

Water Wetter is a surfactant, basically a soap, which by itself can be corrosive. Its main purpose is to reduce the surface tension of the water agaist the cooling system internal surfaces, thus maximizing heat transfer. It's effectiveness can be difficult to quantify.

Softened water by use of ion-exchange resin, doesn't remove contaminating anions from the water. It simply exchanges the calcium and magnesium cations in the untreated water for sodium ions obtained from the rock salt employed in the repetitive resin regeneration process. Softened water works better with soaps and detergents, less well with people who need a low-sodium diet.

Making a 50% solution of basic ethylene glycol antifreeze with steam-distilled grocery-store water works well and gives you the confidence of knowing what is and what isn't in the dilution water. The anti-corrosion additives in regular antifreeze (not containing OAT, "organic acid technology" such as that in Dexcool) should provide lasting corrosion protection with most metals.

Of course, at the end of operating season, there's nothing wrong with draining, flushing, and compressed-air blow-drying the cooling system of your model!

 

[xander janssen]

Interesting discussion as I'm currently building my first liquid cooled engine. It will run only a few hours/year so would be interesting to know what is the best solution (type of coolant and drain yes or no) given the combination of brass, steel, copper and bronze.

 

[WisJim]

Around here there is reverse osmosis water readily available, but not steam distilled. How does that compare to steam distilled or ion-exchange purified water?

 

[Mike1]

I use ready mixed Antifreeze Coolant obtainable at any automotive accessory stockists, I drain down after running the engine while it's warm the coolant can be be reused.

 

[colby15642]

Around here there is reverse osmosis water readily available, but not steam distilled. How does that compare to steam distilled or ion-exchange purified water?

Steam-distilled water will have some trace minerals in it due to its loosely-controlled commercial process, but it won't damage your steam iron or lead-acid battery if you use it to top them off.

De-ionized water is almost completely free of mineral contamination, but is more aggressive corrosion-wise because the missing calcium and magnesium salts are what buffer the water's pH to a near neutral 7. The de-ionization process requires two resin exchanges, one to exchange the cations (Ca & Mg for instance) for H+ (hydronium) ions and the second to exchange the anions for OH- (hydroxide) ions. during the process, the lonely H2 and OH ions instantly combine to form pure H2O (hydrogen hydroxide or pure water, something you should not consume in mass quantities).

Plain ion-exchanged water is the same thing as softened water. After softening, the only cations it contains are sodium (Na+). They are in the form of salts such as sodium carbonate converted from calcium carbonate (lime or CaCO3) for instance. In this example, the sodium carbonate is actually washing soda, a common laundry additive that makes soap "soapier" and prevents the formation of soap scum (calcium stearate). You may be disappointed to learn that calcium stearate is used as a food and cosmetic additive to provide thickening, but as they say, "waste not, want not".

Steam-distilled and de-ionized water taste oddly terrible because of the virtually total absence of taste-imparting trace minerals.

Water is one of the most complex simple compounds you'll encounter in everyday life. I hope this clarifies a few points. All of this information can be found online.

 

[colby15642]

Around here there is reverse osmosis water readily available, but not steam distilled. How does that compare to steam distilled or ion-exchange purified water?

Reverse Osmosis ("RO") removes most mineral salts from water, maybe leaving up to 10% of the original concentration. The RO process reportedly is less effective in removing some trace organic compounds. For model engine cooling purposes, RO filtered water should be acceptable. Since RO water is basically un-buffered, the corrosion potential remains unless anti-corrosion additives, such as those contained in commercial antifreeze are mixed in.

 

[Daniel Williams]

OK, turns out that Aquafina bottled water is RO water. No wonder I can't stand the taste! So that plus regular good old green anti-freeze is the coolant of choice, and I need to incorporate a drain tap on my engine cooling system for draining after a show.
Thanks!

 

[reichpaul630]

I'm wondering about the "red" antifreeze that is being used in some cars now. I heard that the red stuff is "better" for mixed-metal engines (iron, brass, aluminum) that the green stuff. anyone hazard a guess?

 

[colby15642]

The orange Dexcool and similar G05 Ford, and red VW spec antifreezes work best of all on mixed metal systems, as long as long as one of the mixed metals is NOT lead-based solder. I learned that the hard way over the last 20 years. I accidentally became an expert in solder bloom in vintage radiators!

Most auto parts stores now sell a single antifreeze that is supposedly safe for all systems. I would trust it for most systems except those cooling very high output engines or in the case of an antique fire truck that has a $7000 radiator core. Some of the special antifreeze types today are formulated for extended periods between changes. As long as you are changing the solution each season or on a yearly basis and after only a few running hours, the choices are less critical.

 

[Steamchick]

Interesting discussion... When I worked for the local car maker (up to 1/2 million cars per year) I was involved with the development of Local sourced anti-freeze Long-Life Coolant for filling the cars as new. It had to be effectively the same recipe as the imported Japanese stuff, but due to European Health and Safety laws, etc. and commercial confidentiality, the recipe was chemically different - But no-one knows exactly what! We did however, have to install a local water ion exchange filter system on the water supply, to prevent a combination of "stuff" in the LLC mixing with "other stuff" in the local water and causing a deposit that would precipitate out of solution over time, so could (in theory) cause a cooling system deterioration. But the water changed daily (a mix of ground water and collected rainfall) so that was based on using the "worst" water 100% of the time.
But for model engines, ANY regular coolant you would use in your multi thousand dollar car is good enough for your multi-thousand dollar prize model engine. I fact I have changed coolant (3 year service recommendation) on my car with the Prestone solution mentioned above. I would use it or similar branded stuff on anything of a similar nature.
Not expert advice, but a caution that the water is as important as the coolant mix, and de-ionised (ion exchange filtered) water should be good enough. The mixture of De-ionised water and regular Long-Life Coolant has the right additives to minimise any corrosion effects of the De-ionised water, and bi-metal electro-chemical reactions in the system..
Just my "Opinion"...
K2

 

[gbritnell]

As I mentioned I use 50/50 coolant. My engines all have iron cylinder liners and/or heads. Once a year I drain the coolant so I can take the radiator off and give it a complete polishing. I have never had any rusty coolant come out of it. Engine:6061 aluminum and iron. Water pump: aluminum, stainless steel and bronze. Rad: copper and brass with 50/50 soldered joints. 302 v-8 has at least 50 hours of running time with no visible detrimental affects. Just saying!

 

[peterl95124]

As I mentioned I use 50/50 coolant. My engines all have iron cylinder liners and/or heads. Once a year I drain the coolant so I can take the radiator off and give it a complete polishing. I have never had any rusty coolant come out of it. Engine:6061 aluminum and iron. Water pump: aluminum, stainless steel and bronze. Rad: copper and brass with 50/50 soldered joints. 302 v-8 has at least 50 hours of running time with no visible detrimental affects. Just saying!

George, the rust might not be in the coolant ?, Peter.

 

[minh-thanh]

Quite a while ago I bought the best coolant, - as advertised !?
I tested it by: pouring some coolant into a small jar and soaking a few small parts that failed, including brass, iron, and cast iron.
In about 1 week they are fine, 2 weeks there is a little rust - very little, in 1 month it is more rust, but not more than 2 times than in 2 weeks
So, if the engine I run is frequent I will leave the coolant in the system, if the engine is only a few runs and will be on the shelf for a long time - a few months, a year - I will clean the coolant in the system

 

[kf2qd]

Coolant in a car radiator is possibly affected similar to boiler fluid in a steam engine. In a fairly closed system, as it is heated it tends to drive out the air and oxygen and make the solution fairly inert. The antifreeze has some components that help with corrosion resistance.

DI water is very corrosive. Worked for a company building welding equipment that used DI water in the torch coolant with the conductors going to the torch running inside the coolant hoses. The copper wire would be very very clean, and then would just not be there. Dissolved into the DI water. So we substituted RV Antifreeze.

 

[Maris Dislers]

Ethylene glycol is corrosive. Coolants containing it have additives to protect engine parts. These degrade with exposure to air but provide adequate protection in a closed cooling system, for the recommended service interval. Not suitable for vintage cars with cooling systems open to atmosphere - and perhaps model engines. Alternative non-glycol coolants for those vehicles are much safer and provide superior heat transfer. Perhaps if the particular model engine is not exposed below freezing, a non-glycol coolant would be a better option.

 

[Steamchick]

Thanks Maris. Something new to learn every day! Probably why closed systems in modern vehicles use it but the domestic central heating does not!
A friend went ona winter holiday, thinking his house would be kept frost-free over the duration because the heating was left ON at a low thermostat setting. He came home to find the house flooded, needing full rebuild of interiors as all the plaster was water damaged, etc.
There had been a power cut for hours during a very cold night, so his central heating and other pipework had burst in many places... Cost many thousands to rectify and a year of grief and re-build. His heating system had corrosion inhibitor but not anti-freeze....
K2