RV antifreeze

[tunahead72 2,412]

Steve @wh500special started a topic last year about an RV antifreeze shortage.  I didn't want to intrude on that thread, but I do want to start a more general discussion to answer some questions....

 

For reference, this is Steve's topic:

RV’ers. A bizarre shortage. - non tractor related discussion - RedSquare Wheel Horse Forum

 

We've been using the pink stuff to winterize our place in Virginia for years, mostly to fill all the traps and the toilet in the house, with good results.

 

The other day I picked up several gallons of the Traveller brand RV antifreeze at Tractor Supply, and noticed that it's a blend of water, ethanol and several other chemicals.

 

I did a little research, and found that there seems to be three different levels of RV antifreeze on the market, all safe for potable water, etc.:

1.  The inexpensive stuff, with ethanol, burst protection to -50 degrees F, inexpensive at maybe $5 a gallon or so.

2.  A "premium" formulation, propylene glycol based, burst protection to -50 degrees F, more expensive at about $15-$20 a gallon.

3.  The most expensive formulation, haven't checked ingredients, burst protection to -100 degrees F, labels mention protection for engines, about $30 and up per gallon.

 

I'm no chemist, so I have some questions:

 

Are there any problems with using the ethanol based products for winterizing a home?

 

Is there any reason to use the more expensive propylene glycol based products instead?

 

Can the two formulations be mixed?

 

Has the availability of these products changed over the years?  As in, are the manufacturers now pushing more of the ethanol based products because of a possible shortage of propylene glycol like Steve mentioned, or something else?

 

I'm curious what you guys have to say.

 

[Pullstart 62,838]

*edit *Methanol is my subject here.  Not ethanol.  
 

Random.  Methanol is the first product off a moonshine still.  That’s the part that the moonshiners customarily dump at first pour.  I’d imagine there is a more efficient way to produce straight ethanol and less moonshine, but it’s just corn based.  I can’t see (pun?) how it could harm your home for winterization…

 

 

Edited October 27, 2022 by Pullstart

[squonk 41,076]

$4 bucks a gal at Lowes here in NY $3.79 at TSC.

 

We use Proplyene Glycol in heating loops. I pumped 500 gallons into a system at the hospital with AHU's on the roof with heating coils in them. Nasty stuff gooey and likes to eat things over time like valves and pump seals. Some schools I was in used plain antifreeze and we know how nice it is to play with that. 

Edited October 27, 2022 by squonk

[lynnmor 7,305]

For my RV, I always bought the kind without ethanol because of the possibility of ethanol eating seals and it is a fire hazard.  Well last spring the toilet was a black disgusting mess when we de-winterized. So this year I bought the cheap stuff at Rural King for $2.99.

[wh500special 2,170]

Ed,

 

If we are lucky @dcrage will see this.  I think I recall that he's a chemist whereas I'm just a Chemical Engineer.

 

First, chemicals that end in "-ol" are typically alcohols.  Ethanol, Methanol, Isopropanol, Butanol, Cholesterol, etc.  It means that somewhere on them they have a paired oxygen and hydrogen (-OH) group hanging off of them.  This gives them some unique properties (like relatively high boiling points for their molecular weights) since this group likes to stick to other things around it.  It also provides a site for some chemical reactions to take root, so it can be useful for some things. 

 

The Oxygen that is drug along is one of the things that makes alcohols useful additives for gasoline.  It helps "oxygenate" the fuel for better burning.

 

They've likely changed the RV antifreeze formula to an ethanol-based supply due to some ongoing propylene glycol shortages or price increases.  Propylene Glycol is widely used as a starting material for other process and also in cosmetics and whatnot, so it may have elevated value in comparison to ethanol.  I think the ethanol/PG price has probably flipflopped recently due to the worldwide upheaval we've seen in the last few years.  If it flips again, so will the formulation (probably).

 

Ethanol is the alcohol that we drink.  Our bodies have enzymes and digestive systems that can metabolize ethanol in certain doses.  As far as I know, we don't metabolize propylene glycol and it likely just passes on through the system in reasonable doses.  When I was reading the safety info on the PG RV antifreeze last year I found something that it was assumed to be non-toxic by analysis but hadn't actually been tested.  This isn't unreasonable since you don't ingest it in appreciable quantities.

 

On the other hand, Methanol is poisonous and is the fraction in the distilling process that gets thrown away.  It has a significantly lower boiling point than the ethanol that the moonshiner is trying to keep, so it comes out of the still first.  It MUST be thrown away or you can go blind, be horribly poisoned, or die if you consume it.  I didn't watch @Pullstart video, but if they have methanol and ethanol interchanged it's a big problem.  I don't remember why it's poisonous, but I think it is metabolizable by the body into a poison whereas some things will pass right through.  Curiously, the treatment for methanol ingestion is to rapidly and profusely infuse ethanol into the body to displace it.

 

You can mix these two RV formulations into each other harmlessly, but I don't know what to expect it will do to the freezing point as there is often a weird mixing effect with alcohols with respect to freeze point.  It probably maintains a low freeze point, but I don't really know.  I'd use - and we are using - whatever is available and not giving it any additional consideration.

 

I wouldn't pay more for one formulation over the other.  Just use whichever is convenient.

 

Plumbing systems should be tolerant to any of these RV formulations.  You shouldn't have much (if any) aluminum in your plumbing and that would be the other thing that might be suspect that I can think of.  But even in that case it's likely to be a non-issue.

 

Steve

[Pullstart 62,838]

@wh500special right.  Thanks for fact checking my statement!

[tunahead72 2,412]

58 minutes ago, lynnmor said:

... the possibility of ethanol eating seals ...

 

I am a little concerned about that issue, but not a lot.  It's possible I've been using the ethanol based products for years, I never thought to look at the labels closely until recently.  And the only reason I'm curious about it now is that the cheap stuff that Ace Hardware is selling these days is actually more of a purple color, not pink, and it got me to wondering.

 

14 minutes ago, wh500special said:

...  On the other hand, Methanol is poisonous ...

 

Methanol is actually one of the ingredients in the Traveller product from TSC.

 

Thanks guys, I appreciate all the input so far! 

 

[953 nut 55,197]

Last spring while wandering around Wallyworld I saw a clearance display of Prestone RV Antifreeze for $ 2.00 each so I stocked up. It is  nonflammable Ethylene Glycol.

[tunahead72 2,412]

Hmmm...  I don't believe I've ever seen that. 

 

[wh500special 2,170]

that’s weird that they’d put methanol and ethylene glycol into a product intended for

use in a potable water system.  Both of those things are poisonous.  
 

I assume the intention would be to dilute it sufficiently then decontaminate it prior to putting back into service. But why tempt fate?

 

But it’s all about the dose…

 

 

Steve

Edited October 28, 2022 by wh500special

[953 nut 55,197]

9 hours ago, wh500special said:

that’s weird that they’d put methanol and ethylene glycol into a product intended for

use in a potable water system.  Both of those things are poisonous.  
 

I assume the intention would be to dilute it sufficiently then decontaminate it prior to putting back into service. But why tempt fate?

 

But it’s all about the dose…

 

 

Steve

The RV antifreeze is to be used in drain traps and toilets, not the domestic water storage tank and line. My RV had a small compressor that kept the domestic water system pressurized when I was not connected to a water supply. For winter layup I would drain the tank, run the compressor and open faucets one at a time to blow the fresh water out. The water heater had its own drain.