The right coolant....by a different name !!

[Guest Maj Millard]

Years ago when I acquired my 582 Drifter, the late Bill Starke put me onto the right coolant. Bill ran a radiator shop here in Townsville, actually manufactured radiator cores, and around here in Summer you'd better know what coolant to use and recommend.

 

The only coolant he had any time for was (back then) Castrol anti-freeze Anti- boil 30/30. He swore by it, stating that it had a patented seal lubricant in it, which you needed in the 582 to keep the water pump seals in good shape. It certainly worked for me as when I sold the aircraft many years later (650 hrs TT) it still had the original water- pump seals in it. I carried around a new set of seals and the tools to fit them for years, but never got to use them.

 

Bill would also say that a lot of 'coolants' on the shelves of auto stores, were nothing more than de-mineralised water with food colouring in them !..

 

I continued to use this coolant exclusively in my 912 when I acquired the Lightwing, plus in my vehicles, and in many hard working 912 powered bush/station aircraft, which I serviced as a Level 2. Many of these aircraft operating in above 40 C conditions up this way, in the middle of the Northern summers.

 

The original was in a yellow container, and of course always mixed 50/50 with demineralised water as still recommended by Rotax. Ethylene Glycol when mixed with water enhances the water molecules ability to carry heat, so used alone is not much good at all.

 

The product then changed to Valvolene Antiboil- anti freeze in a white container when Valvolene bought Castrol. Same lovely green stuff, still with the patented seal lubricant.

 

It then went through another name change to Valvolene protection plus, antifreeze-Antiboil concentrate 3/80 !.....white container .

 

I recently went to purchase some and it is now ZEREX G-50 formula coolant, antifreeze anti boil in a new gold container !!......same lovely reliable stuff...still mixed 50/50 with demineralised water for our use.

 

Don't know why manufacturers have to keep changing a products appearance, as all it does is confuse consumers. However I don't care as long as the product remains unchanged, and as good as it's always been.................Maj..

 

 

[Vev]

Hi Major,

 

I dont think Valvoline ever bought Castrol.

 

I'm quite sure the chemistry between these products is very different and come from different sources ... Not much in common in terms of these formulations mate.... Sorry!

 

Nothing wrong with either product, but they are not the same .. I think the dye colour is even different too.

 

Cheers

 

Vev

 

 

[cooperplace]

Ethylene Glycol when mixed with water enhances the water molecules ability to carry heat,.............Maj..

Really? I don't think so. Do you have any justification for this statement please?

 

 

[planesmaker]

100% glycol has a no pressure boiling temp around 180'C but add a little water it drops dramatically even 90% is only around 130'C or maybe less I can't remember the exact figure now. Tom

 

 

[cscotthendry]

Don't know why manufacturers have to keep changing a products appearance, as all it does is confuse consumers. ................Maj..

Maj: that's so they can put the price up and the punters think they're getting a "new improved" product.

When I strap an aircraft to my backside, I prefer to use what the engine manufacturer reccommends. For my 912ULS, that's Evans NPG+ which I think is propylene glycol.

 

WADR to your mate who owned a radiator shop, I would expect that most of his products would have been used in automotive applications and that's a different cuttle of fish to an aircraft application. Car engines spend their working life at 30% throttle or less. Aircraft engines spend their life at 75% or More.

 

 

[cooperplace]

100% glycol has a no pressure boiling temp around 180'C but add a little water it drops dramatically even 90% is only around 130'C or maybe less I can't remember the exact figure now. Tom

well, that's it: ethylene glycol improves the corrosion, freezing and boiling point characteristics of water coolant, but it actually has worse heat transfer ability. The glycol/water mix is better but still not as good as pure water. It is highly toxic to humans but the antidote, luckily, is alcohol, preferably in a form with lots of water. Beer is ideal, lots of it.

 

 

[Guest Maj Millard]

It appears that I may have been mistaken..........Castrol is now part of the BP group, it says so on the container. The Zerex coolant is actually in a grey container, and is a Valvolene product.

 

The Castrol product which appears to be the same is now called Radicool concentrate.

 

 

They appear to be similar or the same product.

 

Cscotthendry, Evans npg+ is only one recommended coolant for the 912 Engines. Refer to the latest Rotax SB 'Recommended lubricants and coolants' ..Many choose not to use Evans waterless in this country because of increased cost of purchase, and lack of availability in more remote areas in this country. It is a matter of opinion wether it does a better job anyway.

 

Cooperplace..........straight 'pure water' has no where near the capability of a water/ glycol mix, and is not recommended by Rotax. Rotax and most other engine manufacturers specifically recommend demineralized water only, as a 50/50 mix with a Glycol based coolant concentrate. It is a brave man indeed who would be foolish enough to run pure water in anything these days. Most engines now have alloy cylinder heads and other components, which do definitely require some form of corrosion protection, lest they disappear in just a few years of service. Additionally, water pump and other seals need lubrication and protection that pure water would not provide.......................Maj...

 

 

[facthunter]

Pure water will remove heat quicker than most things ( oil, alcohol. glycol etc.) Glycol raises the boiling point and lowers the freezing point. 100 degrees C is not hot enough to run engines, so you pressurise the system to raise the BP There is a practical limit to this (Usually about 1 bar). Adding a SALT to water will make it remove heat better but many salts are corrosive

 

Glycol may prevent local hot spotting in the water jackets, by raising the Boiling point , and that helps keep the coolant from venting as well. Glycol is very penetrating and leaks easily. It provides no corrosion protection and ages to something quite corrosive and has a limited life. Coolants today almost require a degree to follow the complexities of their formulations and applications. The old green Castrol concentrate was out of production 3 or more years ago. Caltex make a product called XL Corrosion Inhibitor Concentrate, with a 5 year life. It offers no antifreeze or antiboil function, but it's chemically stable., and competitively priced. Use pure water with it. Modern engines stipulate more complex solutions so follow makers recommendations. Nev

 

 

[Guest Maj Millard]

Pure water will remove heat quicker than most things ( oil, alcohol. glycol etc.) Glycol raises the boiling point and lowers the freezing point. 100 degrees C is not hot enough to run engines, so you pressurise the system to raise the BP There is a practical limit to this (Usually about 1 bar). Adding a SALT to water will make it remove heat better but many salts are corrosiveGlycol may prevent local hot spotting in the water jackets, by raising the Boiling point , and that helps keep the coolant from venting as well. Glycol is very penetrating and leaks easily. It provides no corrosion protection and ages to something quite corrosive and has a limited life. Coolants today almost require a degree to follow the complexities of their formulations and applications. The old green Castrol concentrate was out of production 3 or more years ago. Caltex make a product called XL Corrosion Inhibitor Concentrate, with a 5 year life. It offers no antifreeze or antiboil function, but it's chemically stable., and competitively priced. Use pure water with it. Modern engines stipulate more complex solutions so follow makers recommendations. Nev

Facthunter, Incorrect...the 'old green Castrol coolant' as you state is still very much available , but in different forms and containers. I have not noticed any additional 'leakage' on any engine over several years of usage with glycol based products.

 

My many years of usage of this product in many aircraft and vehicles over the years speaks for itself, and is basic non- negotiable proof in my experience. I would not drive or fly with anything else in my radiator.............Maj...

 

 

[geoffreywh]

As an aside

 

 

 

Quote "Car engines spend their working life at 30% throttle or less. Aircraft engines spend their life at 75% or More ".

 

I've seen this statement quoted quite often and whilst correct it appears to credit the aero engine with some sort of mystical property. Yes aero engines spend their lives at 75% max output. And do it for long periods ....I am grateful for that....But.. this setting is particularly easy on an engine. Up and down the rev range with vastly differing loads + hundreds of cold starts is harder on an engine! ....Plus the specific output of an aero engine bhp/ltr is abysmal. ( 0-200 is 30 hp/ltr IF you are lucky !) So you have a great big engine loafing along at steady throttle not doing a whole lot of work. A Honda car engine of similar size puts out 3 or 4 times as much..(and probably costs about 80% less ) Please, give credit where it's due........................................

 

 

[Guest Andys@coffs]

I thought one of the benefits of the NPG+ was that I recall (hopefully correctly) the manufacturer states it has no life limitations, that is, it doesn't need to ever be replaced.......I don't know if that's true in Rotax's or aircraft in general, but to me something that costs double an alternate but never needs to be changed is worth more than an alternate that needs to be swapped regularly.......

 

There is an interesting webpage on why it is compulsory in some rotaxen and seriously recommended for the others here:-

 

http://www.rotaxservice.com/rotax_tips/rotax_feed4.htm

 

Andy

 

 

[facthunter]

IF there is any seepage on combustion products into the coolant it will be degraded with time, by that contamination, so changing the coolant frequently is a good idea.. Never ever use PEE or bore water, salt water etc in your radiator unless the Indians are coming over the hill. Nev

 

 

[Guest Maj Millard]

Suggest you read it again Andy....it is only recommended when a particular engine / radiator installation exceeds normal range and wants to operate at the top end of the range. IE: too hot !....

 

In my experience most 912s operate at the other end of the range (ie: cold) so certainly don't need Evans npg+, in fact I, and many others have to partially cover their radiators and/or oil cooler, just to keep normal operating temps in the recommended range.

 

Another side effect I came across recently when servicing an Evans equipped aircraft. The coolant overflow bottle was found to be empty. When I questioned the owner about this his reply was " oh it's got Evans in it don't worry about it !"........very much wrong , and very much the wrong assumption.....................Maj...

 

 

[cscotthendry]

As an aside 

 

Quote "Car engines spend their working life at 30% throttle or less. Aircraft engines spend their life at 75% or More ".

 

Honda car engine of similar size puts out 3 or 4 times as much..(and probably costs about 80% less ) Please, give credit where it's due........................................

That's true, but if you ran that Honda at 75% of its rated output, it wouldn't be nearly as reliable, as an aircraft engine. A 1200cc 4cyl Honda engine probably would redline somewhere near the 7,000 RPM point (just a guess) but a Rotax 912 is only supposed to go to 5,800 and the reason is the stress on the components at the higher revs shortens the life of the engine. That's why aircraft engines Seem to be loafing they're "de-rated" for reliability. If you put a stock auto engine in a race car, you'd see a very much shortened life expectancy. In fact, I'd be willing to bet you wouldn't get much more than two or three races out of a stock engine. The same would be true if you put a stock honda engine in an airplane. You'd probably get great performance out of it for the first couple of flights and then find yourself in a paddock shortly thereafter.

 

 

[cooperplace]

straight 'pure water' has no where near the capability of a water/ glycol mix, and is not recommended by Rotax. Rotax and most other engine manufacturers specifically recommend demineralized water only, as a 50/50 mix with a Glycol based coolant concentrate. It is a brave man indeed who would be foolish enough to run pure water in anything these days. Most engines now have alloy cylinder heads and other components, which do definitely require some form of corrosion protection, lest they disappear in just a few years of service. Additionally, water pump and other seals need lubrication and protection that pure water would not provide.......................Maj...

I 100% agree you'd have to be a nitwit to use just water, be it tap water, deionised, distilled, or whatever, in an engine. But it does have the best ability to take heat away. Clearly the reduction in heat transfer capacity that results from using a 50/50 glycol/water mix is not a limiting factor in a properly designed cooling system. At risk of sticking my neck out, I think it's best to go with the manufacturer's recommendations!

 

 

[facthunter]

There's all sorts of problems with foaming etc and scouring out of fine tubing in alloy radiators When the glycol goes off it quite corrosive. Deteriorated coolant is far worse than pure water. I don't recommend running for long with either, but I often flush out with frequent changes of pure water. I'm with Maj on the Evan's in the 912's. The average installation doesn't have the overheating problems requiring it. , unless the radiator is mounted near horizontal. The price of coolants these days is a bit over the top. You can buy the ingredients in bulk from china for bu&&er all. Big mark up Nev

 

 

[Guest Maj Millard]

I don't touch the lower -end coolants of doubtfully quality, at whatever savings. The quality green stuff that I use and recommend, is good for two years. Considering you only need around two litres for a 912, it's great value as the rest ends up in the car, or in the wife's car, or whatever.

 

It does the job just fine as my temps always seem to be at the bottom end of the green, even with the radiator half blanked in summer, and both radiator and oil cooler half blanked during the colder months.........Maj...